Information recording medium and system controller

ABSTRACT

An information recording medium for recording a real-time file containing real-time data in such a manner that the real-time data is continuously reproducible by a playback reference model, the real-time data including at least one of video data and audio data. The playback reference model includes: a pickup for reading the real-time data from the information recording medium; a buffer memory for temporarily storing the real-time data read by the pickup; and a decoder module for reading the real-time data from the buffer memory for processing. The information recording medium includes a volume space for at least recording in sectors a file containing data and file management information for managing the file. The real-time data is recorded in at least two real-time extents each of which is allocated in logically contiguous sectors within the volume space. An (i+1) th  real-time extent among the at least two real-time extents is positioned at a position satisfying a real-time reproduction condition.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an information recording mediumfor recording general data (e.g., programs) and/or real-time data (e.g.,video data and/or audio data) thereon on a sector-by-sector basis; amethod for recording data on the information recording medium; a methodfor reproducing data on the information recording medium; and a systemcontroller, an information recording apparatus, and an informationreproduction apparatus for performing such methods.

[0003] 2. Description of the Related Art

[0004] Optical disks are representative of information recording mediahaving a sector structure. The recent trend for higher density, largercapacity, and multimedia technologies has shed light on optical disks asinformation media for use with personal computers and various consumeruse apparatuses.

[0005] Hereinafter, by referring to the accompanying figures, a DVD-RAMdisk will be described as an example of a conventional rewritableoptical disk. FIG. 16A illustrates the physical layout of a conventionalrewritable optical disk of a ZCLV (zoned constant linear velocity)format.

[0006] As shown in FIG. 16A, the rewritable disk includes a lead-inarea, a DMA (defect management area), a data area, and a lead-out area,in this order from the inner periphery to the outer periphery. The DMAis used for managing defective sectors on the disk. Each area hasdigital data recorded therein. The digital data is managed in unitswhich are commonly referred to as sectors. The data area includes aspare area used for replacing a defective sector in a replacementprocess, as well as regions denoted as zones 0 to 34. In each zone, datais recorded in physical sectors which are 2048 bytes long.

[0007] As shown in FIG. 16B, information areas on the rewritable opticaldisk have physical sector numbers (PSN) assigned thereto. User data maybe recorded in a space which is defined as a volume space includinglogical sectors to which logical sector numbers (LSN) are assigned.Stated otherwise, the volume space is the information area minus thelead-in area, the DMA, the unused regions within the spare area, anynumber of defective sectors which are registered in a primary defectlist (PDL) within the DMA, guard regions in between the respectivezones, and the lead out region. In order to provide improved datareliability, an error correction process is performed on an ECCblock-by-ECC block basis, where each ECC (error correction code) blockis composed of 16 logical sectors.

[0008] Any defective sectors which have been detected through a certifyprocess performed at the time of initialization of the disk areregistered in the PDL, so that these defective sectors will not receiveany LSNs assigned thereto. Therefore, it is possible that sectors ofconsecutive logical addresses may include regions which are not in aphysically consecutive order. Any defective sectors which are detectedduring data recording are subjected to a linear replacement whereby theentire ECC block containing each defective area is replaced by a spareregion, and are registered in a secondary defect list (SDL) within theDMA. Thus, a rewritable disk is provided with a mechanism for improvingdata reliability.

[0009] As described above, a DVD-RAM disk, which is provided with adefect management mechanism, is subjected to a defect management processby a drive. On the other hand, a CD-RW disk which is not provided withany defect management mechanism, is subjected to a defect managementprocess—similar to the aforementioned SDL-based defect management—whichis performed by a file system based on a sparing table as defined underthe UDF® (universal disk format) specification of OSTA. Specifically, inthe case of CD-RW disks, the entire ECC block including a defectivesector is replaced by a spare area which is set within the volume space,and this replacement information is managed based on a sparing table asdefined under the UDF specification.

[0010] Next, as an example of a conventional write-once optical disk, a3.95 Gbyte DVD-R as specified under the DVD-R Standards (Version 1.0)will be described. It is assumed that the volume/file structures conformto the data structures defined under the ISO/IEC 13346 Standards or theUDF specification, unless otherwise specified.

[0011]FIG. 17 illustrates an exemplary directory structure to berecorded on an optical disk. Under a ROOT directory 201 is recorded aREALTIME directory 202, which is dedicated to video applications. Underthe REALTIME directory 202, audio/video data (hereinafter referred to as“AV data”) which has been compressed in the MPEG format is recorded in afile named VIDEO.VRO file 203. A number of still picture files whichhave been recorded by means of a digital camera or the like are recordedin a file named FILEA.DAT 204.

[0012]FIGS. 18A to 18C are diagrams illustrating extent locations in thecase where AV data is appended to the VIDEO.VRO file. As used herein, an“extent” means a region containing logically contiguous sectors in whichdata is recorded.

[0013] When AV data is recorded, a linking loss area 561 (32 KB) isfirst recorded, and thereafter AV data is recorded in an extent 562, andfurthermore a padding area 563, in which 00h data is recorded, isrecorded in the sectors up to the ECC block boundary. In the case of DVDdisks, an ECC error correction is performed in units of 16 sectors, sothat data recording also occurs in units of 16 sectors. Next, a filestructure concerning this DVD-R disk is recorded. After a border-out(not shown) is recorded so as to enable reading by a read-only system, arecording area will be formed after the padding area 563. The border-outhas a size of 10 to 100 MB.

[0014] In the case of a DVD-R disk in which data is sequentiallyrecorded, AV data will be sequentially appended, beginning from theinner periphery of an unrecorded area which is left in the outerperiphery of the disk. Therefore, in a second append operation, as shownin FIG. 18B, after a linking loss area 564, AV data is recorded in anextent 565, and a padding area 566 is recorded in the sectors up to theECC block boundary.

[0015] Similarly, as shown in FIG. 18C, in a third AV data appendoperation, a linking loss area 567, an extent 568, and a padding area569 are recorded. Thus, AV data is appended in split portions over anumber of extents.

[0016] Next, a linking scheme for DVD-R disks will be described withreference to FIGS. 19A to 19D. A so-called “buffer underrun” occurs dueto the difference between the data rate of the AV data to be recordedand the data rate when the data is recorded on the disk by the pickup.If a buffer underrun occurs, the drive temporarily suspends therecording, and resumes recording after a predetermined amount of data isstored within the buffer. At this time, the linking scheme forms alinking loss area.

[0017]FIG. 19A is a diagram illustrating extent locations in the casewhere two buffer underruns occur during AV data recording. Extents 222,223, and 224 represent areas in which AV data has been recorded. Alinking loss area 220 is an area which is recorded prior to therecording of AV data. Linking loss areas 226 and 227 are areas which arerecorded responsive to the buffer underruns.

[0018]FIGS. 19B and 19C are sector-by-sector illustrations of areastructures. The linking loss area 220 is recorded by recording 00h dataso as to begin in the middle of the first sector and reach the end ofthe 16 th sector. If an ensuing extent 222 is to be recorded, the extent222 is recorded from the beginning of the first sector up to thebeginning in the next sector adjoining this extent, and the recordingoperation is finished for the time being. Next, when the linking lossarea 226 is to be recorded, the recording is resumed in the middle ofthe first sector. Thus, since a data append operation for DVD-R disksoccurs in the middle of a sector, any sector that contains areas whichare adjoined by the linking scheme is referred to as a linking sector225.

[0019] The specific linking scheme to be performed within a linkingsector is illustrated in FIG. 19D. One sector consists of 26 syncframes. Reference numerals 241, 242, 243, and 244 represent areas whichare recorded at an end portion when the extent 222 is recorded; 241 and242 represent a sync portion and a data portion, respectively, of afirst sync frame; and 243 and 244 represent a sync portion and a dataportion, respectively, of a second sync frame. The data portions 242 and244 are sized so as to be able to allow 91 bytes and 86 bytes of data,respectively, to be recorded therein. An area 245 and the followingareas represent areas which are formed within the first sector of theECC block in the linking loss area 226 when the extent 223 is recorded.Reference numeral 245 represents a data portion in the second syncframe. Reference numerals 246 and 247 represent sync portions in syncframes.

[0020] Data 00h is recorded in a runout area 228 so as not be finalizedat the time of recording the extent 222. A region 229 spanning from the82nd byte to the 87 bytes in the second sync frame is a region whichoverwrites a previously recorded area through appending; this area isreferred to as a linking gap because no valid data can be recordedtherein. Thus, the linking sector 225 containing the linking gap 229 issubject to the physical constraint that data cannot be properly recordedtherein. Therefore, the 32 KB ECC block containing this linking sectoris defined as a linking loss area so as to ensure that any data thatrequires reliability is prevented from being recorded therein as validdata.

[0021] However, in the case where real-time data is reproduced from anoptical disk having the aforementioned format with the real-time databeing recorded thereon, it is difficult to continuously reproduce therecorded real-time data because access may have to occur to physicallynon-contiguous areas which are formed between or within extents.

[0022] In particular, in the case where data is recorded in aconventional file system, the data reproduction may be interrupted dueto a data read delay occurring when accessing a guard area provided inthe vicinity of a zone boundary, a read delay arising from any defectivesectors or defective blocks that are registered in the PDL or SDL,and/or a data read delay arising from bouncing from one recording areato another to access data recorded in a plurality of discrete, emptyareas.

[0023] Since it is currently impossible to distinguish real-time filesfrom general files, once an error occurs during the reproduction ofreal-time data, a delay may occur in order to again reproduce a locationwhich was not successfully reproduced previously.

[0024] Since no identification information is currently available toshow conditions for reproducing real-time data and the fact that givenreal-time data was in fact recorded under such conditions, it isimpossible to know whether or not the recorded real-time data can becontinuously reproduced.

[0025] In the case where a recording apparatus appends real-time data toan already-recorded real-time file, it may not be possible to achievecontinuous data reproduction between the end portion of thealready-recorded data and the beginning portion of the appended data.

[0026] In the case of real-time data which has been encoded by the MPEGmethod, it may not be possible to achieve continuous data reproductionbetween the end portion of the already-recorded data and the beginningportion of the appended data due to differing encoding conditions.

[0027] In the case of an optical disk to which data is recorded whileusing a linking scheme, e.g., a DVD-R disk, a linking loss area which is32 KB long is formed every time a buffer underrun occurs. This causeseach area in which data is recorded to be split into a plurality ofextents, resulting in a large amount of address information beingassociated with each extent to be managed by the file system, making itdifficult to reproduce the data by means of a reproduction-onlyapparatus with a limited memory size. Moreover, when AV data having alow data rate is recorded, linking loss areas to be recorded willaccount for a large proportion, resulting in a poor recordingefficiency.

SUMMARY OF THE INVENTION

[0028] According to one aspect of the present invention, there isprovided an information recording medium for recording a real-time filecontaining real-time data in such a manner that the real-time data iscontinuously reproducible by a playback reference model, the real-timedata including at least one of video data and audio data, wherein theplayback reference model includes: a pickup for reading the real-timedata from the information recording medium; a buffer memory fortemporarily storing the real-time data read by the pickup; and a decodermodule for reading the real-time data from the buffer memory forprocessing, wherein the information recording medium includes a volumespace for at least recording in sectors a file including data and filemanagement information for managing the file; the real-time data isrecorded in at least two real-time extents each of which is allocated inlogically contiguous sectors within the volume space; and an (i+1)^(th)real-time extent among the at least two real-time extents is positionedat a position satisfying a real-time reproduction condition defined as:T(i)≦(B(i−1)+D(i))/Vout, wherein: T(i) represents a time required forthe pickup to access from an end of an i^(th) real-time extent among theat least two real-time extents to a beginning of the (i+1)^(th)real-time extent; B(i) represents an amount of data having been storedin the buffer memory when the pickup accesses from the end of the i^(th)real-time extent to the beginning of the (i+1)^(th) real-time extent,such that B(i)=B(i−1)+D(i)−Vout×T(i), assuming that B(0)=0, D(i)represents an increase in the amount of data having been stored in thebuffer memory responsive to the pickup reading the data from the i^(th)real-time extent, such that D(i)=(Vin−Vout)×S(i)/Vin, wherein D(i) iscorrected at least to a value equal to or smaller than M−B(i−1) whenD(i) >M−B(i−1), where M represents a size of the buffer memory; Voutrepresents a data transfer rate when the data is transferred from thebuffer memory to the decoder module; Vin represents a data transfer ratewhen the data is read from each of the at least two real-time extents bythe pickup and transferred to the buffer memory; and S(i) represents adata size of the i^(th) real-time extent.

[0029] In one embodiment of the invention, D(i) is corrected so thatD(i)=(Vin−Vout)×S(i)/Vin+B(i−1)−k×(Vout×Tk) when D(i)>M−B(i−1), wherein:Tk represents a maximum rotation wait time of the information recordingmedium; and k represents an integer portion of((D(i)+B(i−1)−M)/(Vout×Tk)+1).

[0030] In another embodiment of the invention, each of the at least tworeal-time extents is allocated in physically contiguous sectors.

[0031] In still another embodiment of the invention, the file managementinformation includes location information indicating each of the atleast two real-time extents.

[0032] In still another embodiment of the invention, the file managementinformation includes first identification information for identifyingthe real-time file including real-time data.

[0033] In still another embodiment of the invention, the file managementinformation includes second identification information for indicatingthat the at least two real-time extents are positioned in accordancewith the real-time reproduction condition.

[0034] In still another embodiment of the invention, the file managementinformation includes, as an extended attribute, information representinga condition under which the at least two real-time extents werepositioned.

[0035] Alternatively, there is provided an information recording mediumfor recording a real-time file containing real-time data in such amanner that the real-time data is continuously reproducible by aplayback reference model, the real-time data including at least one ofvideo data and audio data, wherein the playback reference modelincludes: a pickup for reading the real-time data from the informationrecording medium; a buffer memory for temporarily storing the real-timedata read by the pickup; and a decoder module for reading the real-timedata from the buffer memory for processing, wherein the informationrecording medium includes a volume space for at least recording insectors a file including data and file management information formanaging the file; the real-time data is recorded in at least tworeal-time extents each of which is allocated in logically contiguoussectors within the volume space; and an (i+12)^(th) real-time extentamong the at least two real-time extents is positioned at a positionsatisfying a real-time reproduction condition defined as:T(i)≦(B(i−1)+D(i))/Vout, wherein: T(i) represents a time required forthe pickup to access from an end of an i^(th) real-time extent among theat least two real-time extents to a beginning of the (i+1)^(th)real-time extent; B(i) represents an amount of data having been storedin the buffer memory when the pickup accesses from the end of the i^(th)real-time extent to the beginning of the (i+1)^(th) real-time extent,such that B(i)=B(i−1)+D(i)−Vout×T(i), assuming that B(0)=0, D(i)represents an increase in the amount of data having been stored in thebuffer memory responsive to the pickup reading the data from the i^(th)real-time extent, such that D(i)=(Vin−Vout)×S(i)/Vin, wherein D(i) iscorrected at least to a value equal to or smaller than M−B(i−1) whenD(i)>M−B(i−1), where M represents a size of the buffer memory; Voutrepresents a data transfer rate when the data is transferred from thebuffer memory to the decoder module; Vin represents a data transfer ratewhen the data is read from each of the at least two real-time extents bythe pickup and transferred to the buffer memory; and S(i) represents adata size of the i^(th) real-time extent, wherein the real-time file isa file in which the real-time data is appended; and wherein data of analready recorded real-time extent is recorded in a newly recordedreal-time extent.

[0036] In one embodiment of the invention, D(i) is corrected so thatD(i)=(Vin−Vout)×S(i)/Vin+B(i−1)−k×(Vout×Tk) when D(i)>M−B(i−1), wherein:Tk represents a maximum rotation wait time of the information recordingmedium; and k represents an integer portion of((D(i)+B(i−1)−M)/(Vout×Tk)+1).

[0037] In another embodiment of the invention, each of the at least tworeal-time extents is allocated in physically contiguous sectors.

[0038] In still another embodiment of the invention, the file managementinformation includes location information indicating each of the atleast two real-time extents.

[0039] In still another embodiment of the invention, the file managementinformation includes first identification information for identifyingthe real-time file including real-time data.

[0040] In still another embodiment of the invention, the file managementinformation includes second identification information for indicatingthat the at least two real-time extents are positioned in accordancewith the real-time reproduction condition.

[0041] In still another embodiment of the invention, the file managementinformation includes, as an extended attribute, information representinga condition under which the at least two real-time extents werepositioned.

[0042] Alternatively, there is provided an information recording mediumfor recording a real-time file containing real-time data in such amanner that the real-time data is continuously reproducible by aplayback reference model, the real-time data including at least one ofvideo data and audio data, wherein the playback reference modelincludes: a pickup for reading the real-time data from the informationrecording medium; a buffer memory for temporarily storing the real-timedata read by the pickup; and a decoder module for reading the real-timedata from the buffer memory for processing, wherein the informationrecording medium includes a volume space for at least recording insectors a file including data and file management information formanaging the file; the real-time data is recorded in at least tworeal-time extents each of which is allocated in logically contiguoussectors within the volume space; and an (i+1)^(th) real-time extentamong the at least two real-time extents is positioned at a positionsatisfying a real-time reproduction condition defined as:T(i)≦(B(i−1)+D(i))/Vout, wherein: T(i) represents a time required forthe pickup to access from an end of an i^(th) real-time extent among theat least two real-time extents to a beginning of the (i+1)^(th)real-time extent; B(i) represents an amount of data having been storedin the buffer memory when the pickup accesses from the end of the i^(th)real-time extent to the beginning of the (i+1)^(th) real-time extent,such that B(i)=B(i−1)+D(i)−Vout×T(i), assuming that B(0)=0, D(i)represents an increase in the amount of data having been stored in thebuffer memory responsive to the pickup reading the data from the i^(th)real-time extent, such that D(i)=(Vin−Vout)×S(i)/Vin, wherein D(i) iscorrected at least to a value equal to or smaller than M−B(i−1) whenD(i)>M−B(i−1), where M represents a size of the buffer memory; Voutrepresents a data transfer rate when the data is transferred from thebuffer memory to the decoder module; Vin represents a data transfer ratewhen the data is read from each of the at least two real-time extents bythe pickup and transferred to the buffer memory; and S(i) represents adata size of the i^(th) real-time extent, wherein the real-time file isa file in which the real-time data is appended; wherein the real-timedata is compressed in an MPEG format; and wherein data including one ormore GOPs recorded at an end of the real-time file before appending isre-encoded and is recorded in a newly recorded real-time extent.

[0043] In one embodiment of the invention, D(i) is corrected so thatD(i)=(Vin−Vout)×S(i)/Vin+B(i−1)−k×(Vout×Tk) when D(i)>M−B(i−1), wherein:Tk represents a maximum rotation wait time of the information recordingmedium; and k represents an integer portion of((D(i)+B(i−1)−M)/(Vout×Tk)+1).

[0044] In another embodiment of the invention, each of the at least tworeal-time extents is allocated in physically contiguous sectors.

[0045] In still another embodiment of the invention, the file managementinformation includes location information indicating each of the atleast two real-time extents.

[0046] In still another embodiment of the invention, the file managementinformation includes first identification information for identifyingthe real-time file including real-time data.

[0047] In still another embodiment of the invention, the file managementinformation includes second identification information for indicatingthat the at least two real-time extents are positioned in accordancewith the real-time reproduction condition.

[0048] In still another embodiment of the invention, the file managementinformation includes, as an extended attribute, information representinga condition under which the at least two real-time extents werepositioned.

[0049] Alternatively, there is provided an information recording mediumincluding a volume space for at least recording in sectors a fileincluding data and file management information for managing the file,wherein: the data includes real-time data, the real-time data includingat least one of video data and audio data; the real-time data isrecorded in at least one real-time extent each of which is allocated inlogically contiguous sectors within the volume space; the file includesat least one real-time extent; a linking loss extent is positionedbefore each of the at least one real-time extent; and a linking gap isformed in the at least one real-time extent.

[0050] In one embodiment of the invention, the linking loss extentincludes one ECC block.

[0051] In another embodiment of the invention, the file managementinformation includes location information indicating each of the atleast one real-time extent.

[0052] In still another embodiment of the invention, the file managementinformation includes identification information for identifying thereal-time file including real-time data.

[0053] In still another embodiment of the invention, a data type bit isrecorded in an area for recording physical additional informationconcerning each sector within the linking loss extent, the data type bitbeing used for identifying the linking loss extent; and wherein the datatype bit for the sector is set to 1 if a next sector is included withinthe linking loss extent, unless the sector is a linking sector.

[0054] In still another embodiment of the invention, wherein a runoutarea is formed before the linking gap; and the real-time data isrecorded in the runout area within the linking loss extent.

[0055] According to another aspect of the present invention, there isprovided, a method for recording a real-time file containing real-timedata on an information recording medium in such a manner that thereal-time data is continuously reproducible by a playback referencemodel, the real-time data including at least one of video data and audiodata, wherein the playback reference model includes: a pickup forreading the real-time data from the information recording medium; abuffer memory for temporarily storing the real-time data read by thepickup; and a decoder module for reading the real-time data from thebuffer memory for processing, wherein the information recording mediumincludes a volume space for at least recording in sectors a fileincluding data and file management information for managing the file,the real-time data is recorded in at least one real-time extent each ofwhich is allocated in logically contiguous sectors within the volumespace, wherein the method includes the steps of: searching for at leasttwo areas satisfying a real-time reproduction condition from among aplurality of logically contiguous unused areas within the volume space,each of the at least two areas being designated as a pre-allocated area,an (i+1)th pre-allocated area among the at least two areas satisfyingthe real-time reproduction condition being defined as:T(i)≦(B(i−1)+D(i))/Vout, wherein: T(i) represents a time required forthe pickup to access from an end of an i^(th) pre-allocated area amongthe at least two pre-allocated areas to a beginning of the (i+1)^(th)pre-allocated area; B(i) represents an amount of data having been storedin the buffer memory when the pickup accesses from the end of the i^(th)pre-allocated area to the beginning of the (i+1)^(th) pre-allocatedarea, such that B(i)=B(i−1)+D(i)−Vout×T(i), assuming that B(0)=0, D(i)represents an increase in the amount of data having been stored in thebuffer memory responsive to the pickup reading the data from the i^(th)pre-allocated area, such that D(i)=(Vin−Vout)×S(i)/Vin, wherein D(i) iscorrected at least to a value equal to or smaller than M−B(i−1) whenD(i)>M−B(i−1), where M represents a size of the buffer memory; Voutrepresents a data transfer rate when the data is transferred from thebuffer memory to the decoder module; Vin represents a data transfer ratewhen the data is read from the pre-allocated area by the pickup andtransferred to the buffer memory; and S(i) represents a data size of thei^(th) pre-allocated area; recording the real-time data in thepre-allocated area; designating a set of logically contiguous sectors inwhich real-time data is recorded as a real-time extent; and recordingthe file management information for managing the real-time data as thereal-time file.

[0056] In one embodiment of the invention, D(i) is corrected so thatD(i)=(Vin−Vout)×S(i)/Vin+B(i−1)−k×(Vout×Tk) when D(i)>M−B(i−1), wherein:Tk represents a maximum rotation wait time of the information recordingmedium; and k represents an integer portion of((D(i)+B(i−1)−M)/(Vout×Tk)+1).

[0057] In another embodiment of the invention, each of the at least onepre-allocated area is allocated in physically contiguous sectors on anECC block-by-ECC block basis.

[0058] In still another embodiment of the invention, the file managementinformation includes location information indicating each of the atleast two real-time extents.

[0059] In still another embodiment of the invention, the file managementinformation includes first identification information for identifyingthe real-time file including real-time data.

[0060] In still another embodiment of the invention, the file managementinformation includes second identification information for indicatingthat the at least two real-time extents are positioned in accordancewith the real-time reproduction condition.

[0061] In still another embodiment of the invention, the file managementinformation includes, as an extended attribute, information representinga condition under which the at least two real-time extents werepositioned.

[0062] Alternatively, there is provided a method for recording areal-time file containing real-time data on an information recordingmedium in such a manner that the real-time data is continuouslyreproducible by a playback reference model, the real-time data includingat least one of video data and audio data, wherein the playbackreference model includes: a pickup for reading the real-time data fromthe information recording medium; a buffer memory for temporarilystoring the real-time data read by the pickup; and a decoder module forreading the real-time data from the buffer memory for processing,wherein the information recording medium includes a volume space for atleast recording in sectors a file including data and file managementinformation for managing the file, the real-time data is recorded in atleast one real-time extent each of which is allocated in logicallycontiguous sectors within the volume space, wherein the method includesthe steps of: calculating whether or not each of the at least onereal-time extent will cause an overflow in an amount of data stored inthe buffer memory if the real-time extent is reproduced by the playbackreference model; when it is calculated that the real-time extent willcause an overflow, correcting the amount of data stored in the buffermemory to equal to or smaller than the size of the buffer memory;calculating whether or not an underflow will occur in the amount of datastored in the buffer memory if the playback reference model accessesfrom the real-time extent to a newly-allocated pre-allocated area; whenit is calculated that an underflow will occur, searching for a real-timeextent which will not cause an underflow, on accessing from thereal-time extent to the pre-allocated area; recording in thenewly-allocated pre-allocated area the real-time data already recordedin the real-time extent which will cause an underflow; recordingreal-time data to be appended in the newly-allocated pre-allocated area;designating a set of logically contiguous sectors in which real-timedata is recorded as a real-time extent; and recording the filemanagement information.

[0063] In one embodiment of the invention, each of the at least onepre-allocated area is allocated in physically contiguous sectors on anECC block-by-ECC block basis.

[0064] In another embodiment of the invention, the file managementinformation includes location information indicating each of the atleast one real-time extent.

[0065] In still another embodiment of the invention, the file managementinformation includes first identification information for identifyingthe real-time file including real-time data.

[0066] In still another embodiment of the invention, the file managementinformation includes second identification information for indicatingthat the at least two real-time extents are positioned in accordancewith the real-time reproduction condition.

[0067] In still another embodiment of the invention, the file managementinformation includes, as an extended attribute, information representinga condition under which the at least two real-time extent werepositioned.

[0068] According to yet another aspect of the present invention, thereis provided a method for appending a real-time file containing real-timedata on an information recording medium in such a manner that thereal-time data is continuously reproducible by a playback referencemodel, the real-time data including at least one of video data and audiodata, wherein the playback reference model includes: a pickup forreading the real-time data from the information recording medium; abuffer memory for temporarily storing the real-time data read by thepickup; and a decoder module for reading the real-time data from thebuffer memory for processing, wherein the information recording mediumincludes a volume space for at least recording in sectors a fileincluding data and file management information for managing the file,the real-time data is recorded in at least one real-time extent each ofwhich is allocated in logically contiguous sectors within the volumespace, wherein the real-time file includes data which is compressed inan MPEG format, wherein the method includes the steps of: reading datarecorded at an end of the real-time file before appending, the dataincluding one or more GOPs; re-encoding the data which has been read;recording the re-encoded data in a newly allocated pre-allocated area;recording real-time data to be appended in the newly-allocatedpre-allocated area; designating a set of logically contiguous sectors inwhich real-time data is recorded as a real-time extent; and recordingthe file management information.

[0069] In one embodiment of the invention, each of the at least onepre-allocated area is allocated in physically contiguous sectors on anECC block-by-ECC block basis.

[0070] In another embodiment of the invention, the file managementinformation includes location information indicating each of the atleast one real-time extent.

[0071] In still another embodiment of the invention, the file managementinformation includes first identification information for identifyingthe real-time file including real-time data.

[0072] In still another embodiment of the invention, the file managementinformation includes second identification information for indicatingthat the at least two real-time extents are positioned in accordancewith the real-time reproduction condition.

[0073] In still another embodiment of the invention, the file managementinformation includes, as an extended attribute, information representinga condition under which the at least two real-time extents werepositioned.

[0074] Alternatively, there is provided a method for recordinginformation on an information recording medium including a volume spacefor at least recording in sectors a file including data and filemanagement information for managing the file, including the steps of:determining whether or not the file is a real-time file containingreal-time data; recording the file management information in the volumespace; recording the real-time data next to a linking loss extent if thefile is determined to be a real-time file; and responsive to a bufferunderrun occurring during the recording of the real-time data, forming alinking gap in a real-time extent in which the real-time data isrecorded.

[0075] In one embodiment of the invention, the linking loss extentincludes one ECC block.

[0076] In another embodiment of the invention, the file managementinformation includes location information indicating each real-timeextent.

[0077] In still another embodiment of the invention, the file managementinformation includes identification information for identifying thereal-time file including real-time data.

[0078] In still another embodiment of the invention, a data type bit isrecorded in an area for recording physical additional informationconcerning each sector within the linking loss extent, the data type bitbeing used for identifying the linking loss extent; and wherein the datatype bit for the sector is set to 1 if a next sector is included withinthe linking loss extent, unless the sector is a linking sector.

[0079] In still another embodiment of the invention, the method furtherincludes a step of recording the real-time data in a runout area withinthe linking loss extent.

[0080] According to yet another aspect of the present invention, thereis provided an information recording apparatus for recording a real-timefile containing real-time data on an information recording medium insuch a manner that the real-time data is continuously reproducible by aplayback reference model, the real-time data including at least one ofvideo data and audio data, wherein the playback reference modelincludes: a pickup for reading the real-time data from the informationrecording medium; a buffer memory for temporarily storing the real-timedata read by the pickup; and a decoder module for reading the real-timedata from the buffer memory for processing, wherein the informationrecording medium includes a volume space for at least recording insectors a file including data and file management information formanaging the file; wherein the information recording apparatus includesa file system processing section for: allocating at least two areassatisfying a real-time reproduction condition from among a plurality oflogically contiguous unused areas within the volume space, each of theat least two areas being designated as a pre-allocated area; recordingthe real-time data and the file management information; designating aset of logically contiguous sectors in which real-time data is recordedas a real-time extent; and generating the file management informationfor managing the real-time data as the real-time file, wherein an(i+1)^(th) pre-allocated area among the at least two pre-allocated areasis positioned at a position satisfying a real-time reproductioncondition defined as: T(i)≦(B(i−1)+D(i))/Vout, wherein: T(i) representsa time required for the pickup to access from an end of an i^(th)pre-allocated area among the at least two pre-allocated areas to abeginning of an (i+1)^(th) pre-allocated area among the at least twopre-allocated areas; B(i) represents an amount of data having beenstored in the buffer memory when the pickup accesses from the end of thei^(th) pre-allocated area to the beginning of the (i+1)^(th)pre-allocated area, such that B(i)=B(i−1)+D(i)−Vout×T(i), assuming thatB(0)=0, D(i) represents an increase in the amount of data having beenstored in the buffer memory responsive to the pickup reading the datafrom the i^(th) pre-allocated area, such that D(i)=(Vin−Vout)×S(i)/Vin,wherein D(i) is corrected at least to a value equal to or smaller thanM−B(i−1) when D(i)>M−B(i−1), where M represents a size of the buffermemory; Vout represents a data transfer rate when the data istransferred from the buffer memory to the decoder module; Vin representsa data transfer rate when the data is read from the pre-allocated areaby the pickup and transferred to the buffer memory; and S(i) representsa data size of the i^(th) pre-allocated area.

[0081] In one embodiment of the invention, D(i) is corrected so thatD(i)=(Vin−Vout)×S(i)/Vin+B(i−1)−k×(Vout×Tk) when D(i)>M−B(i−1), wherein:Tk represents a maximum rotation wait time of the information recordingmedium; and k represents an integer portion of((D(i)+B(i−1)−M)/(Vout×Tk)+1).

[0082] In another embodiment of the invention, each of the at least onepre-allocated area is allocated in physically contiguous sectors on anECC block-by-ECC block basis.

[0083] In still another embodiment of the invention, the file managementinformation includes location information indicating each real-timeextent.

[0084] In still another embodiment of the invention, the file managementinformation includes first identification information for identifyingthe real-time file including real-time data.

[0085] In still another embodiment of the invention, the file managementinformation includes second identification information for indicatingthat the at least two real-time extents are positioned in accordancewith the real-time reproduction condition.

[0086] In still another embodiment of the invention, the file managementinformation includes, as an extended attribute, information representinga condition under which the at least two real-time extents werepositioned.

[0087] According to yet another aspect of the present invention, thereis provided an information recording apparatus for appending a real-timefile containing real-time data on an information recording medium insuch a manner that the real-time data is continuously reproducible by aplayback reference model, the real-time data including at least one ofvideo data and audio data, wherein the playback reference modelincludes: a pickup for reading the real-time data from the informationrecording medium; a buffer memory for temporarily storing the real-timedata read by the pickup; and a decoder module for reading the real-timedata from the buffer memory for processing, wherein the informationrecording medium includes a volume space for at least recording insectors a file including data and file management information formanaging the file, the real-time data is recorded in at least onereal-time extent each of which is allocated in logically contiguoussectors within the volume space, wherein the information recordingapparatus includes: a data amount calculation section for calculatingwhether or not each of the at least one real-time extent will cause anoverflow in an amount of data stored in the buffer memory if thereal-time extent is reproduced by the playback reference model;correcting the amount of data stored in the buffer memory to equal to orsmaller than the size of the buffer memory when it is calculated thatthe real-time extent will cause an overflow; calculating whether or notan underflow will occur in the amount of data stored in the buffermemory if the playback reference model accesses from the real-timeextent to a newly-allocated pre-allocated area; and searching for areal-time extent which will not cause an underflow, on accessing fromthe real-time extent to the pre-allocated area when it is calculatedthat an underflow will occur; a data recording section for recording inthe newly allocated pre-allocated area the real-time data alreadyrecorded in the real-time extent which will cause an underflow, andrecording real-time data to be appended in the newly-allocatedpre-allocated area; and a file structure processing section fordesignating a set of logically contiguous sectors in which real-timedata is recorded as a real-time extent and for generating and recordingthe file management information.

[0088] In one embodiment of the invention, each of the at least onepre-allocated area is allocated in physically contiguous sectors on anECC block-by-ECC block basis.

[0089] In another embodiment of the invention, the file managementinformation includes location information indicating each of the atleast one real-time extent.

[0090] In still another embodiment of the invention, the file managementinformation includes first identification information for identifyingthe real-time file including real-time data.

[0091] In still another embodiment of the invention, the file managementinformation includes second identification information for indicatingthat the at least two real-time extents are positioned in accordancewith the real-time reproduction condition.

[0092] In still another embodiment of the invention, the file managementinformation includes, as an extended attribute, information representinga condition under which the at least two real-time extents werepositioned.

[0093] Alternatively, there is provided an information recordingapparatus for appending a real-time file containing real-time data on aninformation recording medium in such a manner that the real-time data iscontinuously reproducible by a playback reference model, the real-timedata including at least one of video data and audio data, wherein theplayback reference model includes: a pickup for reading the real-timedata from the information recording medium; a buffer memory fortemporarily storing the real-time data read by the pickup; and a decodermodule for reading the real-time data from the buffer memory forprocessing, wherein the information recording medium includes a volumespace for at least recording in sectors a file including data and filemanagement information for managing the file, the real-time data isrecorded in at least one real-time extent each of which is allocated inlogically contiguous sectors within the volume space, wherein thereal-time file includes data which is compressed in an MPEG format,wherein the information recording apparatus includes: a re-encodingsection for reading data recorded at an end of the real-time file beforeappending, the data including one or more GOPs, re-encoding the datawhich has been read, and recording the re-encoded data in a newlyallocated pre-allocated area; and a file structure processing sectionfor designating a set of logically contiguous sectors in which real-timedata is recorded as a real-time extent and for generating and recordingthe file management information.

[0094] In one embodiment of the invention, each of the at least onepre-allocated area is allocated in physically contiguous sectors on anECC block-by-ECC block basis.

[0095] In another embodiment of the invention, the file managementinformation includes location information indicating each of the atleast two real-time extents.

[0096] In still another embodiment of the invention, the file managementinformation includes first identification information for identifyingthe real-time file including real-time data.

[0097] In still another embodiment of the invention, the file managementinformation includes second identification information for indicatingthat the at least two real-time extents are positioned in accordancewith the real-time reproduction condition.

[0098] In still another embodiment of the invention, the file managementinformation includes, as an extended attribute, information representinga condition under which the at least two real-time extents werepositioned.

[0099] Alternatively, there is provided an information recordingapparatus for recording information on an information recording mediumincluding a volume space for at least recording in sectors a fileincluding data and file management information for managing the file,including: a recording mode determination section for determiningwhether or not the file is a real-time file containing real-time data; afile structure processing section for recording the file managementinformation in the volume space; a linking setting section for recordingthe real-time data next to a linking loss extent if the file isdetermined to be a real-time file; and a linking controller for,responsive to a buffer underrun occurring during the recording of thereal-time data, forming a linking gap in a real-time extent in which thereal-time data is recorded.

[0100] In one embodiment of the invention, the linking loss extentincludes one ECC block.

[0101] In another embodiment of the invention, the file managementinformation includes location information indicating each real-timeextent.

[0102] In still another embodiment of the invention, the file managementinformation includes identification information for identifying thereal-time file including real-time data.

[0103] In still another embodiment of the invention, the linkingcontroller records a data type bit in an area for recording physicaladditional information concerning each sector within the linking lossextent, the data type bit being used for identifying the linking lossextent; and wherein the data type bit for the sector is set to 1 if anext sector is included within the linking loss extent, unless thesector is a linking sector.

[0104] In still another embodiment of the invention, the recordingapparatus further includes a runout controller for recording thereal-time data in a runout area within the linking loss extent.

[0105] According to yet another aspect of the present invention, thereis provided a system controller for an information recording apparatusfor recording a real-time if file containing real-time data on aninformation recording medium in such a manner that the real-time data iscontinuously reproducible by a playback reference model, the real-timedata including at least one of video data and audio data, wherein theplayback reference model includes: a pickup for reading the real-timedata from the information recording medium; a buffer memory fortemporarily storing the real-time data read by the pickup; and a decodermodule for reading the real-time data from the buffer memory forprocessing, wherein the information recording medium includes a volumespace for at least recording in sectors a file including data and filemanagement information for managing the file; wherein the systemcontroller includes a file system processing section for: allocating atleast two areas satisfying a real-time reproduction condition from amonga plurality of logically contiguous unused areas within the volumespace, each of the at least two areas being designated as apre-allocated area; recording the real-time data and the file managementinformation; designating a set of logically contiguous sectors in whichreal-time data is recorded as a real-time extent; and generating thefile management information for managing the real-time data as thereal-time file, wherein an (i+1)^(th) pre-allocated area among the atleast two pre-allocated areas is positioned at a position satisfying areal-time reproduction condition defined as: T(i)≦(B(i−1)+D(i) )/Vout,wherein: T(i) represents a time required for the pickup to access froman end of an i^(th) pre-allocated area among the at least twopre-allocated areas to a beginning of an (i+1)^(th) pre-allocated areaamong the at least two pre-allocated areas; B(i) represents an amount ofdata having been stored in the buffer memory when the pickup accessesfrom the end of the i^(th) pre-allocated area to the beginning of the(i+1)^(th) pre-allocated area, such that B(i)=B(i−1)+D(i)−Vout×T(i),assuming that B(0)=0, D(i) represents an increase in the amount of datahaving been stored in the buffer memory responsive to the pickup readingthe data from the i^(th) pre-allocated area, such thatD(i)=(Vin−Vout)×S(i)/Vin, wherein D(i) is corrected at least to a valueequal to or smaller than M−B(i−1) when D(i)>M−B(i−1), where M representsa size of the buffer memory; Vout represents a data transfer rate whenthe data is transferred from the buffer memory to the decoder module;Vin represents a data transfer rate when the data is read from the atpre-allocated are by the pickup and transferred to the buffer memory;and S(i) represents a data size of the i^(th) pre-allocated area.

[0106] Alternatively, there is provided a system controller for aninformation recording apparatus for appending a real-time filecontaining real-time data on an information recording medium in such amanner that the real-time data is continuously reproducible by aplayback reference model, the real-time data including at least one ofvideo data and audio data, wherein the playback reference modelincludes: a pickup for reading the real-time data from the informationrecording medium; a buffer memory for temporarily storing the real-timedata read by the pickup; and a decoder module for reading the real-timedata from the buffer memory for processing, wherein the informationrecording medium includes a volume space for at least recording insectors a file including data and file management information formanaging the file, the real-time data is recorded in at least onereal-time extent each of which is allocated in logically contiguoussectors within the volume space, wherein the system controller includes:a data amount calculation section for calculating whether or not each ofthe at least one real-time extent will cause an overflow in an amount ofdata stored in the buffer memory if the real-time extent is reproducedby the playback reference model; correcting the amount of data stored inthe buffer memory to equal to or smaller than the size of the buffermemory when it is calculated that the real-time extent will cause anoverflow; calculating whether or not an underflow will occur in theamount of data stored in the buffer memory if the playback referencemodel accesses from the real-time extent to a newly-allocatedpre-allocated area; and searching for a real-time extent which will notcause an underflow, on accessing from the real-time extent to thepre-allocated area when it is calculated that an underflow will occur; adata recording section for recording in the newly allocatedpre-allocated area the real-time data already recorded in the real-timeextent which will cause an underflow, and recording real-time data to beappended in the newly-allocated pre-allocated area; and a file structureprocessing section for designating a set of logically contiguous sectorsin which real-time data is recorded as a real-time extent and forgenerating and recording the file management information.

[0107] According to yet another aspect of the present invention, thereis provided a method for reproducing a real-time file containingreal-time data on an information recording medium in such a manner thatthe real-time data is continuously reproducible by a playback referencemodel, the real-time data including at least one of video data and audiodata, wherein the playback reference model includes: a pickup forreading the real-time data from the information recording medium; abuffer memory for temporarily storing the real-time data read by thepickup; and a decoder module for reading the real-time data from thebuffer memory for processing, wherein the information recording mediumincludes a volume space for at least recording in sectors a fileincluding data and file management information for managing the file,wherein the real-time data is recorded in at least two real-time extentseach of which is allocated in logically contiguous sectors within thevolume space; and an (i+1)^(th) real-time extent among the at least tworeal-time extents is positioned at a position satisfying a real-timereproduction condition defined as: T(i)≦(B(i−1)+D(i))/Vout, wherein:T(i) represents a time required for the pickup to access from an end ofan i^(th) real-time extent among the at least two real-time extents to abeginning of the (i+1)^(th) real-time extent; B(i) represents an amountof data having been stored in the buffer memory when the pickup accessesfrom the end of the i^(th) real-time extent to the beginning of the(i+1)^(th) real-time extent, such that B(i)=B(i−1)+D(i)−Vout×T(i),assuming that B(0)=0, D(i) represents an increase in the amount of datahaving been stored in the buffer memory responsive to the pickup readingthe data from the i^(th) real-time extent, such thatD(i)=(Vin−Vout)×S(i)/Vin, wherein D(i) is corrected at least to a valueequal to or smaller than M−B(i−1) when D(i)>M−B(i−1), where M representsa size of the buffer memory; Vout represents a data transfer rate whenthe data is transferred from the buffer memory to the decoder module;Vin represents a data transfer rate when the data is read from each ofthe at least two real-time extents by the pickup and transferred to thebuffer memory; and S(i) represents a data size of the i^(th) real-timeextent, wherein the method includes the steps of: reproducing thereal-time file from the information recording medium by means of a diskdrive; acquiring location information of each of the at least tworeal-time extents and identification information indicating that the atleast two real-time extents are positioned in accordance with thereal-time reproduction condition; reading data from the at least tworeal-time extents at a data transfer rate which is equal to or greaterthan Vin of the playback reference model; temporarily storing thereal-time data which has been read in the buffer memory; reading thedata stored in the buffer memory and decoding the data in a decoder; andaccessing a next real-time extent within the time T(i) of the playbackreference model.

[0108] In one embodiment of the invention, the file managementinformation includes, as an extended attribute, information representinga condition under which the at least two real-time extents werepositioned, the method further including a step of: reading the extendedattribute from the file management information, and informing areproduction mode to the disk drive based on the extended attributeprior to reproduction.

[0109] Alternatively, there is provided a method for reproducingreal-time data from an information recording medium including a volumespace for at least recording in sectors a file including data and filemanagement information for managing the file, wherein: the data includesreal-time data, the real-time data including at least one of video dataand audio data; the real-time data is recorded in at least one real-timeextent each of which is allocated in logically contiguous sectors withinthe volume space; the file includes at least one real-time extent; alinking loss extent is positioned before each of the at least onereal-time extent; and a linking gap is formed in the at least onereal-time extent, wherein the method includes the steps of: determiningwhether or not the file is a real-time file containing real-time data;and performing a reproduction operation for data recorded in a real-timeextent, the reproduction operation being continuously performed withoutperforming a recovery process even if a reproduction error due toinvalid data recorded in the linking gap occurs.

[0110] According to yet another aspect of the present invention, thereis provided an information reproduction apparatus for reproducing areal-time file containing real-time data on an information recordingmedium in such a manner that the real-time data is continuouslyreproducible by a playback reference model, the real-time data includingat least one of video data and audio data, wherein the playbackreference model includes: a pickup for reading the real-time data fromthe information recording medium; a buffer memory for temporarilystoring the real-time data read by the pickup; and a decoder module forreading the real-time data from the buffer memory for processing,wherein the information recording medium includes a volume space for atleast recording in sectors a file including data and file managementinformation for managing the file, wherein the real-time data isrecorded in at least two real-time extents each of which is allocated inlogically contiguous sectors within the volume space; and an (i+1)^(th)real-time extent among the at least two real-time extents is positionedat a position satisfying a real-time reproduction condition defined as:T(i)≦(B(i−1)+D(i))/Vout, wherein: T(i) represents a time required forthe pickup to access from an end of an i^(th) real-time extent among theat least two real-time extents to a beginning of the (i+1)^(th)real-time extent; B(i) represents an amount of data having been storedin the buffer memory when the pickup accesses from the end of the i^(th)real-time extent to the beginning of the (i+1)^(th) real-time extent,such that B(i)=B(i−1)+D(i)−Vout×T(i), assuming that B(0)=0, D(i)represents an increase in the amount of data having been stored in thebuffer memory responsive to the pickup reading the data from the i^(th)real-time extent, such that D(i)=(Vin−Vout)×S(i)/Vin, wherein D(i) iscorrected at least to a value equal to or smaller than M−B(i−1) whenD(i)>M−B(i−1), where M represents a size of the buffer memory; Voutrepresents a data transfer rate when the data is transferred from thebuffer memory to the decoder module; Vin represents a data transfer ratewhen the data is read from each of the at least two real-time extents bythe pickup and transferred to the buffer memory; and S(i) represents adata size of the i^(th) real-time extent, wherein the informationreproduction apparatus includes: a disk drive for reproducing thereal-time file from the information recording medium; a file structureprocessing section for acquiring location information of each of the atleast two real-time extents and identification information indicatingthat the at least two real-time extents are positioned in accordancewith the real-time reproduction condition; a data reproducer for readingdata from the at least two real-time extents at a data transfer ratewhich is equal to or greater than Vin of the playback reference model; abuffer memory for temporarily storing the real-time data which has beenread; and a decoder for reading the data stored in the buffer memory anddecoding the data, wherein a data reproduction performance which isdetermined as a function of an access performance and data transfer rateof the data reproducer and a size of the buffer memory satisfies apredetermined data reproduction performance of the playback referencemodel.

[0111] In one embodiment of the invention, the file managementinformation includes, as an extended attribute, information representinga condition under which the at least two real-time extents werepositioned, the information reproduction apparatus further including: areproduction mode informing section for reading the extended attributefrom the file management information, and informing a reproduction modeto the disk drive based on the extended attribute prior to reproduction.

[0112] Alternatively, there is provided an information reproductionapparatus for reproducing a real-time file containing real-time data onan information recording medium including a volume space for at leastrecording in sectors a file including data and file managementinformation for managing the file, wherein: the data includes real-timedata, the real-time data including at least one of video data and audiodata; the real-time data is recorded in at least one real-time extenteach of which is allocated in logically contiguous sectors within thevolume space; the file includes at least one real-time extent; a linkingloss extent is positioned before each of the at least one real-timeextent; and a linking gap is formed in the at least one real-timeextent, wherein the information reproduction apparatus includes: a filestructure processing section for determining whether or not the file isa real-time file containing real-time data; and a data reproducer forperforming a reproduction operation for data recorded in a real-timeextent, the reproduction operation being continuously performed withoutperforming a recovery process even if a reproduction error due toinvalid data recorded in the linking gap occurs.

[0113] The information recording medium according to the presentinvention, on which real-time extents are positioned so as to satisfy areal-time reproduction condition, utilizes a playback reference model soas to enable reproduction apparatuses to continuously reproducereal-time data. As a result, various reproduction apparatuses cancontinuously reproduce real-time data from the information recordingmedium according to the present invention.

[0114] Since each real-time extent is composed of a physicallycontiguous area, it is possible to calculate underflows occurringresponsive to accesses.

[0115] By providing an area for recording information for identifyingreal-time files from general files in a file management informationarea, it is possible to more effectively perform continuous reproductioneven when errors occur during the reproduction of a real-time file.

[0116] By providing information indicating that a real-time reproductioncondition is satisfied by the real-time extents in the file managementinformation area, it is possible to determine whether or not areproduction apparatus satisfying the prescribed performance of theplayback reference model can continuously reproduce a real-time filefrom the information recording medium according to the presentinvention.

[0117] Even in the case where real-time data is appended to a previouslyrecorded real-time file, it is possible to position or arrange real-timeextents on the information recording medium according to the presentinvention based on the real-time reproduction condition, so that areproduction apparatus can continuously reproduce data from thebeginning of the appended real-time file.

[0118] Even in the case where the appended data is real-time data whichhas been encoded in the MPEG format, it is ensured that a reproductionapparatus can continuously reproduce data by providing an area forrecording re-encoded VOBUs in a newly allocated unrecorded area.

[0119] In accordance with the information recording medium according tothe present invention, even in the case where it is implemented as anoptical disk which records data by using a linking scheme, e.g., a DVD-Rdisk, it is ensured that real-time data is recorded in contiguous areaseven if a buffer underrun occurs while a recording apparatus recordsreal-time data, by providing a real-time extent after a linking lossextent and forming a linking gap within the real-time extent. Byproviding a real-time extent after a linking loss extent, it is possibleto improve data reliability in the beginning portion of the real-timedata.

[0120] By sizing each linking loss extent as one ECC block, it ispossible to further improve data reliability in the beginning portion ofreal-time data.

[0121] By providing an area for recording information for identifying alinking loss extent in an area for recording physical additionalinformation, a reproduction apparatus can recognize, upon detection of alinking gap, that the sector contains unnecessary data, therebysimplifying the designing of reproduction apparatuses.

[0122] By recording valid data in a runout area, it is ensured that theonly areas in which data cannot be recorded will be the linking gapseven if a buffer underrun occurs when a recording apparatus recordsreal-time data, so that the reliability of real-time data can beimproved.

[0123] The recording method according to the present invention iscapable of searching for and allocating real-time extents in such amanner as to realize continuous reproduction of real-time data, bycalculating a data amount within a buffer memory during reproduction.

[0124] In accordance with the recording method according to the presentinvention, areas in which the playback reference model will notexperience overflow or underflow can be calculated before recording ofreal-time data. As a result, it is possible to record data in such amanner that various reproduction apparatuses can continuously reproducereal-time data.

[0125] Even in the case where new real-time data is appended to analready-recorded real-time file, upon detecting that the playbackreference model will experience a buffer underflow, the real-time datarecorded in an area which is considered responsible for the bufferunderflow can be copied to an unrecorded area, whereby data can berecorded in such a manner that a reproduction apparatus can continuouslyreproduce the real-time data.

[0126] In the case where appended data is real-time data which has beenencoded in the MPEG format, the last VOBU in already-recorded AV datacan be re-encoded along with the newly appended data for recording,thereby making it possible to attain seamless reproduction of MPEGstreams.

[0127] The recording method according to the present invention providesan appropriate method of recording data on an optical disk whichutilizes a linking scheme for data recording. For example, sinceinformation relating to an I picture is recorded in the first sector ofMPEG data, the data quality of the first sector is very influential overthe reproduced images and sounds. In the case of high-quality audiodata, too, the data quality of the first sector will determine theimpression of a song at its beginning. Therefore, in the case ofrecording real-time data, every first sector is required to have a highreliability.

[0128] On the other hand, audio/video data which is recorded in extentsrequire continuous recording and continuous reproduction capabilitiesbecause “freezing” of images and sounds, occurring responsive to anaccess, will be more readily recognized than a deterioration in thequality of images and/or sounds due to loss of data.

[0129] In accordance with the recording method according to the presentinvention, the first sector can be recorded so as to succeed a linkingloss extent, so that linking sectors will not be formed, therebycontributing to high data reliability. Since a linking loss extent isnot formed responsive to every instance of buffer underrun, it ispossible to continuously record real-time data.

[0130] Any data that was not successfully recorded due to a linking gapcan be easily error-corrected based on ECCs, because each linking gap isonly several bytes in size.

[0131] Even if a buffer underrun occurs during recording, it is ensuredthat a multitude of linking loss areas will not be formed, therebyproviding for a high recording efficiency. Furthermore, it is possibleto reduce the size of address information pertaining to each real-timeextent, which is managed by a file system.

[0132] In accordance with the reproduction method according to thepresent invention, it is possible to switch between a read command forgeneral data and a read command for real-time data, based on file typeinformation, so that it is possible to realize continuous reproductioneven if a defective sector is detected during the reading of real-timedata.

[0133] The data reproduction performance of the information reproductionapparatus according to the present invention, which is determined as afunction of the access performance and data read performance of areproduction drive and the size of a reproduction buffer memory, isselected so as to satisfy a predetermined data reproduction performancethat is defined by the playback reference model. As a result, continuousreproduction capabilities are provided on any information reproductionapparatuses that share the same data reproduction performance.

[0134] Thus, the invention described herein makes possible theadvantages of (1) providing an information recording medium in the formof a recordable optical disk which enables continuous reproduction ofreal-time data; (2) providing a method for recording data on such aninformation recording medium and a method for reproducing data on suchan information recording medium; and (3) providing an informationrecording apparatus and an information reproduction apparatus to be usedin conjunction with such an information recording medium.

[0135] These and other advantages of the present invention will becomeapparent to those skilled in the art upon reading and understanding thefollowing detailed description with reference to the accompanyingfigures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0136]FIG. 1 is a data structural diagram illustrating area structureson an information recording medium according to Example 1 of the presentinvention.

[0137]FIGS. 2A and 2B illustrate the structure of a playback referencemodel and its access performance, respectively, according to Example 1of the present invention.

[0138]FIG. 3 is a block diagram of the informationrecording/reproduction apparatus according to Example 1 of the presentinvention.

[0139]FIG. 4 is a flowchart illustrating a recording method according toExample 1 of the present invention.

[0140]FIGS. 5A to 5C are diagrams illustrating an exemplary areaarrangement allocated for a real-time file in accordance with therecording method according to Example 1 of the present invention.

[0141]FIG. 6 shows a transition in the amount of data in a buffer memoryas calculated by the recording method according to Example 1 of thepresent invention.

[0142]FIGS. 7A, 7B, and 7C are data structural diagrams illustrating thedata structure of attribute information of a real-time file according toExample 1 of the present invention.

[0143]FIG. 8 is a flowchart illustrating a reproduction method accordingto Example 1 of the present invention.

[0144]FIG. 9 is a block diagram of an information recording/reproductionapparatus according to the present invention.

[0145]FIGS. 10A and 10B illustrate the structure of a playback referencemodel and its access performance, respectively, according to Example 2of the present invention.

[0146]FIG. 11 is a flowchart illustrating a recording method accordingto Example 2 of the present invention.

[0147]FIG. 12 shows a transition in the amount of data in a buffermemory as calculated by the recording method according to Example 2 ofthe present invention.

[0148]FIGS. 13A to 13D are diagrams illustrating an exemplary areaarrangement allocated for a real-time file in accordance with therecording method according to Example 2 of the present invention.

[0149]FIGS. 14A to 14E are data structural diagrams illustrating alinking scheme concerning real-time extents according to Example 2 ofthe present invention.

[0150]FIG. 15 is a data structural diagram illustrating area structureson the information recording medium according to Example 2 of thepresent invention.

[0151]FIGS. 16A and 16B are data structural diagrams illustrating areastructures on a conventional information recording medium.

[0152]FIG. 17 is schematic representation of a directory structure forfiles to be recorded.

[0153]FIGS. 18A to 18C are data diagrams illustrating an extentarrangement in the case where AV data is appended to a VIDEO.VRO file.

[0154]FIGS. 19A to 19D are data structural diagrams illustrating alinking scheme for a DVD-R disk.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0155] Hereinafter, the present invention will be described by way ofillustrative examples, with reference to the accompanying figures.

[0156] Example 1 is directed to an embodiment in which a real-time fileis newly recorded on a DVD-RAM disk. Example 2 is directed to anembodiment in which real-time data is appended to a real-time file whichhas already been recorded on a DVD-R disk.

Example 1

[0157] In the course of our description, the area structures in aninformation recording medium in which files that are managed based on avolume file structure as specified under the ECMA167 Standards (shown inFIG. 1) and a playback reference model and access performanceillustrated in FIGS. 2A and 2B will be first described. Then, a methodfor recording a real-time file on the information recording medium shownin FIG. 1 will be described with reference to a block structural diagramshown in FIG. 3 and a flowchart shown in FIG. 4. Finally, a method forreproducing a real-time file on the information recording medium shownin FIG. 1 will be described with reference to the block structuraldiagram shown in FIG. 3 and a flowchart shown in FIG. 8.

[0158] In the following description, it is assumed that variousdescriptors, pointers, and the like which are recorded in thevolume/file structures of an information recording medium conform to thedata structures defined under the ECMA167 Standards, unless otherwisespecified.

[0159]FIG. 1 is a data structural diagram illustrating the areastructures on an information recording medium in the form of arewritable optical disk according to one embodiment of the presentinvention. As shown in FIG. 1, information areas, which are composed ofphysical sectors, include a lead-in area 101, a DMA area 102, zones 0 to34 (not all of which are shown), and a lead-out area 126. In thebeginning portion of zone 0, a spare area 103 for substituting for adefective sector or a defective block is provided, followed by a volumespace. From the beginning of the volume space, a volume structure area104 for logically handling the information recording medium, and a filestructure area 105 in which a file structure is recorded, are provided.

[0160] Allocated areas 106, 110, 120, 121, 122, and 125 are regions inwhich data have already been recorded. Guard areas 107 and 109, in whichno user data can be recorded, are formed between zone 0 and zone 1, andbetween zone 1 and zone 2, respectively. Although not shown, allocatedareas 120, 122, and 125 include guard areas formed at respective zoneboundaries. In zone 1, real-time extents RT₁ and RT₂, in which real-timedata is recorded, are formed so as to interpose a defective block 108 inbetween, for example. The defective block 108 may be a defective blockwhich has been detected during the recording of general data, whose datais recorded in the spare area 103 as a substitution. In zone 2,real-time extents RT₃ and RT₄ are formed. In zone 3, a pre-allocatedarea A₅ and a real-time extent RT₅ are formed.

[0161] In zone 7, a real-time extent RT₆, an empty extent 123, and anunused area 124 are formed. The real-time extents RT₁ to RT₆ arepositioned in such a manner as to satisfy a set of conditions which aredefined by a playback reference model having a predetermined accessperformance, as described later in more detail. No real-time data isrecorded in the pre-allocated area A₅ because any real-time datarecorded in this area would result in an interruption of continuous datareproduction. In the file structure area 105, a space bit map 141 formanaging unallocated areas (which are capable of allowing data to berecorded therein) within the volume space and file managementinformation having a directory structure as shown in FIG. 17 arerecorded.

[0162] A file entry 142 is management information for managing thelocation information and attribute information of the ROOT directory201. The ROOT directory file includes file identifier descriptors 143and 144. The file identifier descriptors 143 and 144 contain locationinformation of file entries 145 (FILEA.DAT file 204 under the ROOTdirectory 201) and 146 (the REALTIME directory 202 under the ROOTdirectory 201), respectively. The file entry 145 includes locationinformation of the allocated area 106 in which the data of this file isrecorded. The file entry 146 includes location information of a REALTIMEdirectory file, i.e., the file identifier descriptor 147. A fileidentifier descriptor 147 includes location information of a file entry148 for the VIDEO.VRO file 203. The file entry 148 includes locationinformation of real-time extents RT₁ to RT₆, in which real-time data isrecorded, and the empty extent 123.

[0163]FIGS. 2A and 2B illustrate a playback reference model and itsaccess performance for determining conditions for positioning thereal-time data according to one embodiment of the present invention,respectively. The playback reference model shown in FIG. 2A includes adisk 301, a pickup 302 for reading data from the disk 301, a buffermemory 303 for temporarily storing the data that has been read, and adecoder module 304 for decoding the data which has been transferred fromthe buffer memory 303. Vin denotes a data transfer rate whentransferring data from the disk 301 to the buffer memory 303. Voutdenotes a data transfer rate when transferring data from the buffermemory 303 to the decoder module 304. Vin is set at a value which islarger than Vout, which defines the largest data transfer rate for anyreal-time data that is contemplated for each given application.

[0164]FIG. 2B is a graph illustrating a relationship between accessdistances and access times during an access made by the pickup 302 inthe playback reference model. In FIG. 2B, ip(x) is a function whichextracts an integer portion of x. Assuming that n=ip (TI/TS), any accessto an nth sector takes a skip access time, which is an integer functionof an n multiple of single sector latencies TS. For any access thatoccurs astride a zone boundary, a fixed time TZ (“zone boundary crossingtime”) applies. For any access to a position within the same zone, afixed time TI (“intra-zone access time”) applies. For any access to aposition in a neighboring zone, TN (“neighboring zone accesstime)=(2TI+TZ) applies. For any access to a position which is two ormore zones away, a fixed time TL (“long access time”) applies, which issubstantially equal to a full stroke access time required for the pickup302 to travel from the innermost periphery to the outermost periphery.

[0165] This playback reference model is created so as to serve as areference in determining conditions under which continuous reproductionis ensured when reproducing real-time data on an optical disk isreproduced by any one of various types of reproduction apparatuses.Accordingly, each access time in the access performance profile definedin the graph of FIG. 2B are to be determined on the basis of accesstimes which are realizable on various reproduction apparatus which areenvisaged to reproduce the optical disk according to the presentinvention. For example, a portable optical disk player for consumer use,which is required to operate under certain power consumption conditions,incurs longer access times than does an optical disk drive for use witha computer. Under such circumstances, the access performance profiledefined in the graph of FIG. 2B are to be determined on the basis of theaccess times incurred by the portable optical disk player for consumeruse.

[0166] When reading data in accordance with the playback referencemodel, data will be stored in the buffer memory 303 at a rate ofVin−Vout on the other hand, during an access operation of the pickup302, data within the buffer memory 303 will be consumed at a rate ofVout because data cannot be read. By applying specific access timevalues in this operation model, it is possible to quantitativelycalculate variations in the data amount within the buffer memory 303 asthe playback reference model reproduces real-time data. Accordingly, ifdata recording areas are positioned in such a manner that the datawithin the buffer memory 303 does not experience underflowing as theplayback reference model reproduces real-time data, then it is possibleto continuously reproduce real-time data. By means of this modeling,conditions for positioning the real-time extents (in which real-timedata is recorded) can be determined.

[0167] Now, with reference to a block diagram shown in FIG. 3 and aflowchart shown in FIG. 4 of an information recording/reproductionapparatus according to one embodiment of the present invention, a methodfor recording real-time files to the information recording medium shownin FIG. 1 will be described. The information recording/reproductionapparatus includes a system controller 701, an I/O bus 706, an opticaldisk drive 707, an input section 708 for inputting recording modes,etc., a tuner 710 for receiving TV broadcast programs, an encoder 709for encoding video/audio signals into AV data, and a decoder 711 fordecoding the AV data and outputting the decoded AV data to a TV set 712.The system controller 701 includes: a recording mode determinationsection 702, an allocation parameter memory 703, a file systemprocessing section 704, and a file system processing memory 705. Thefile system processing section 704 includes: a reproduction modeinforming section 741, a data amount calculation section 742, a timeinformation calculation section 743, an unallocated area search section744, a physically non-contiguous location acquisition section 745, afile structure processing section 746, a data recording section 747, anda data read section 748. The file system processing memory 705, which isutilized by these sections includes: an empty extent memory 751, a timeinformation memory 752, a pre-allocated area memory 753, a physicallynon-contiguous location memory 754, a file structure memory 755, a bitmap memory 756, a data buffer memory 757.

[0168] It is ensured that the access performance and the recording rateduring data recording of the optical disk drive 707 and the size of thedata buffer memory 757 are chosen so as to provide a data recordingperformance which satisfies a level of recording performance that wouldbe attained by using the playback reference model for recording.

[0169] A recording mode and a recording time are designated via theinput section 708, which may be implemented as a remote control, amouse, or a keyboard. The recording mode determination section 702 firstdetermines whether the data to be recorded is AV data or not, andperforms the subsequent steps if the data to be recorded is AV data. Ifthe data to be recorded is AV data, the recording mode determinationsection 702 determines Vout, which defines a fixed value which is usedto ensure successful recording even in the case where any data to berecorded is continually provided at the maximum data transfer rate; Vin,which defines a read rate from the disk; size SR of data to be recorded;a buffer size Bmax; and various access times, and store these values inthe allocation parameter memory 703. As for real-time data which isrecorded on a DVD-RAM disk, predetermined fixed values for read rate Vinand buffer size Bmax are already retained in the allocation parametermemory 703 in order to clarify the requirements that an apparatus mustsatisfy in order to be able to reproduce that particular real-time. Morethan one set of such fixed values are preset so as to support readdrives which may be relatively faster or slower. The read rate Vindepends on the data to be recorded, and the maximum data transfer ratefor given data that is desired to be recorded by a user may bedesignated for Vin. For example, a relatively large value is set for theread rate Vin in the case of recording in high picture quality mode, anda relatively small value is set for the read rate Vin in the case ofrecording in a long-time mode (Step S801).

[0170] The file structure processing section 746 instructs the data readsection 748 to read the volume structure area 104 and the file structurearea 105, and the data which has been read by the optical disk drive 707is analyzed on the file structure memory 755. A space bit map which isamong the data that has been read is transferred to the bit map memory756. The physically non-contiguous location acquisition section 745instructs the optical disk drive 707 to report location information ofzone boundaries and/or location information of defective blocksregistered in the PDL or SDL, as physically non-contiguous locationinformation on the disk. The physically non-contiguous locationinformation which has been reported from the optical disk drive 707 isretained in the physically non-contiguous location memory 754.

[0171] The unallocated area search section 744 searches for anyunallocated areas which are physically contiguous on an ECC block-by-ECCblock basis as pre-allocated areas, by using the location information ofunallocated areas retained in the bit map memory 756 and the physicallynon-contiguous location information retained in the physicallynon-contiguous location memory 754. The location information of thepre-allocated areas found in the search is stored in the pre-allocatedarea memory 753. This search operation is performed until the total sizeof the pre-allocated areas well exceeds the size of data to be recordedSR as determined at Step S801, so that it will be unnecessary to againperform this step even if any areas which cannot be allocated are foundin later steps.

[0172]FIG. 5A is a diagram illustrating an exemplary arrangement oflocations of pre-allocated areas which have been found as a result ofthe search in this step. Pre-allocated areas A₁ to A₇ are allocated. Inorder to secure the pre-allocated areas, the file structure processingsection 746 updates corresponding pre-allocated regions in the bit mapon the bit map memory 756 to an “allocated” status.

[0173] At this point, all areas that are found to be recordable based onthe space bit map, except for those registered in the SDL, arelogically-contiguous recordable areas because any area that isregistered in the SDL would actually be recorded in the spare area as asubstitution. Moreover, logically-contiguous areas can be determined bysplitting such logically-contiguous areas at the guard areas within eachzone or at the boundaries between the areas registered in the PDL. Thereason for searching for physically-contiguous areas is so that thetransition in the amount of data within the buffer can be moreaccurately calculated in the subsequent steps.

[0174] The reason why the search is performed on an ECC block-by-ECCblock basis is in order to prevent real-time data from being subjectedto a replacement process, as part of defect management, in the casewhere both real-time data and general data are recorded in one ECC block(Step S802).

[0175] The time information calculation section 743 calculates a readtime TR_(i) (where i corresponds to the area number A_(i) forpre-allocated areas as shown in FIG. 5A) required for reading eachpre-allocated area at a data transfer rate of Vin and an access timeT_(i,i+1) between pre-allocated areas (i.e., access time betweenpre-allocated areas A_(i) and A_(i+1) as shown in FIG. 5A), by using thelocation information of pre-allocated areas retained in thepre-allocated area memory 753 and the various access times retained inthe allocation parameter memory 703. The read time TR_(i) is determinedto be S_(i)/Vin, where S_(i) represents the size of each pre-allocatedarea A_(i).

[0176] In FIG. 5A, the read times TR₁ to TR₇ are times required forreading the pre-allocated areas A₁ to A₇, respectively. The access timeT_(1,2) is a read delay time which is ascribable to a defective ECCblock, equal to 16TS. T_(2,3), T_(3,4), T_(4,5), T_(5,6), and T_(6,7),are a zone boundary crossing time TZ, an intra-zone access time TI, aneighboring zone access time TN, an intra-zone access time TI, and along access time TL, respectively. These access times can be derivedfrom the access performance of the playback reference model as shown inFIG. 2B. In order to calculate how the playback reference model wouldreproduce data from pre-allocated areas, the read time for eachpre-allocated area and the access time for a next pre-allocated area arealternately calculated (Step S803).

[0177] Next, the data amount calculation section 742 performscalculation processes from Steps S804 to S813 by using the read timesand access times retained in the time information memory 752, andcalculates the amount of data within the buffer memory at the time whenthe read for pre-allocated areas has completed. FIG. 6 shows atransition in the amount of data in the buffer memory as data in thepre-allocated areas is read. At time t₁, which is after reading of thepre-allocated area A₁, the data amount has increased at a rate of(Vin−Vout), over the time period TR₁ (Step S804).

[0178] Since the buffer memory of an actual reproduction apparatus isfinite, it is necessary to consider the operation at an upper limit ofbuffer size. Therefore, it is checked whether or not the calculated dataamount exceeds the buffer size Bmax (Step S805).

[0179] If overflow does not occur, then, it is checked whether or notthe total calculated size of the pre-allocated areas well exceeds thesize of data to be recorded SR, which was previously set at Step S801.By allocating sufficient recordable areas as pre-allocated areas, it isensured that there will always be enough recordable areas even if areasin which data cannot be recorded due to dust or scratches are avoidedduring actual recording (Step S807).

[0180] If the total calculated size of pre-allocated areas does notexceed SR, then it is checked whether or not the calculated data amountexceeds an allocation level BL (=Vout×TL). If the amount of data withinthe buffer exceeds BL, then underflow will never occur when any area onthe disk is accessed from the end of this pre-allocated area. Therefore,the first pre-allocated area to this pre-allocated area are determinedas areas which will not cause underflowing, and hence these areas areregistered as empty extents in which real-time data can be recorded.Thus, the subsequent steps can be performed in a more efficient manner.When conducting a search for areas associated with underflowing, forexample, it is possible to exclude the areas that have been registeredas empty extents (Step S809) from those which are searched.

[0181] Next, the amount of data within the buffer memory at the time ofstarting a read of pre-allocated areas is calculated. At time t₂ in FIG.5A, which is before reading the pre-allocated area A₂, the data amounthas decreased at a rate of Vout, over the time period T_(1,2) (StepS811).

[0182] It is checked whether or not the calculated data amount has anegative (−) value. If the calculated data amount has a negative (−)value, it means that a buffer underflow will occur responsive to thisaccess, so that the data reproduction will be interrupted (Step S812).

[0183] If the calculated data amount does not have a negative (−) value,the control proceeds to the beginning of Step S804. In FIG. 6, thepre-allocated areas A₂ to A₄ are calculated while repeating Steps 804 toS812.

[0184] With reference to Step S805, the data may overflow the buffer atthe tail end of the pre-allocated area A₄, as shown in FIG. 6. In thiscase, the optical disk drive 707 temporarily suspends the datareproduction operation in order to avoid data overflow; therefore, aminimum rotation wait time is added to TR₄. Accordingly, the calculateddata amount is corrected on the assumption that the data has decreasedat a rate of Vout over a period of k×TK, where TK represents a rotationwait time at the outermost periphery of the information recordingmedium, and k=ip ((B(t)−Bmax)/(Vout×TK)+1)), where ip(x) is a functionwhich extracts an integer portion of x. B(t) represents a data amountwhen overflow occurs. However, in order to simplify the data amountcorrection calculation, Bmax may be regarded as the data amount whenoverflow occurs, although this will result in a lower calculationaccuracy (Step S806).

[0185] Since the data amount exceeds the allocation level BL at time t₇,the pre-allocated areas A₁ to A₄ are allocated as empty extents E₁ toE₄, and the location information there of is stored in the empty extentmemory 751 (Step S810).

[0186] In FIG. 6, the data amount calculation results in the case ofreading the pre-allocated areas A₅ to A₇ are shown by dotted lines. Adata underflow occurs at time t₁₂. In this case, the pre-allocated areawhich is most responsible for the underflow is excluded from allocation,and the control proceeds to the beginning of Step S811. Thepre-allocated area which is most responsible for the underflow can bedetermined based on D_(i), which represents a decrease in the dataamount that occurs between accessing the beginning of an pre-allocatedarea A_(i) and finishing data read from this area. By calculating thedecrease for each pre-allocated area and finding a pre-allocated areawhich has the largest decrease, the pre-allocated area which is mostresponsible for the data underflow can be known.

[0187] Specifically, D₅, D₆, and D₇ in FIG. 6 are calculated. Since D₅is the largest among the three, the pre-allocated area A₅ is excludedfrom allocation. In other words, in FIG. 5B, the area numbers areupdated so that the old pre-allocated areas A₆ and A₇ become newpre-allocated areas A₅* and A₆*, respectively. Furthermore, as shown inFIGS. 4 and 5B, an access time T_(4,5)* between the pre-allocated areasA₄ and A₅* is calculated, and the old read times TR₆ and TR₇ arerenumbered as new read times TR₅* and TR₆*, respectively, and the accesstime T_(6,7) is renumbered as a new access time T_(5,6)*. Since thismethod takes into account access times, a higher calculation efficiencyis provided than by methods in which the pre-allocated areas are omittedone by one from calculation in an ascending order of size (i.e., smallerareas first). If an underflow still occurs after the area associatedwith the largest decrease in data amount is omitted from thecalculation, the area associated with the second largest decrease indata amount is omitted from the calculation, and so on (Step S813).

[0188] Next, the calculation of Step S811 is resumed at time T_(4,5)*.After an increase in data amount from the pre-allocated area A₆* iscalculated, since the total size of the pre-allocated areas exceeds thesize of data to be recorded SR, the pre-allocated areas A₅* and A₆* areallocated as empty extents E₅ and E₆, and the location information thereof is stored in the empty extent memory 751, and the control proceeds toStep 814. Through the flow of control up to this step, areas in whichreal-time data can be recorded have been determined (Step S808).

[0189] In order to indicate that the allocated empty extents are in factpre-allocated for recording real-time data, the file structureprocessing section 746 generates a file entry for the VIDEO.VRO filecontaining location information of the empty extents, and instructs thedata recording section 747 to record data on the disk, so that the fileentry is recorded on the disk by the optical disk drive 707. In the casewhere the system controller accomplishes recording of a plurality offiles in a multi-task environment, the process from Steps S802 to S813may be performed as one process that has precedence over other tasks,and the determined empty extents are registered on the optical diskduring this step. As a result, in a multi-task environment, too, thedata of general files can be prevented from being erroneously recordedin any empty extents determined through the calculation (Step S814).

[0190] An audio/video signal which is input from the tuner 710 isencoded by the encoder 709 into AV data by a variable length compressionmethod, and transferred to the data buffer memory 757. The filestructure processing section 746 instructs the data recording section747 to record the AV data in an already-allocated empty extent, and theAV data is recorded without a replacement process to a spare area. Sincethe data recording performance which is determined as a function of anaccess performance and data read performance of the optical disk drive707 and the size of the reproduction buffer memory 757 satisfies apredetermined data reproduction performance that can be achieved by aplayback reference model during data recording, the data buffer memory757 is not overflowed during data recording.

[0191] As shown in FIG. 5C, the empty extents E₁ to E₅ in whichreal-time data has been recorded become real-time extents RT₁ to RT₅,respectively. Since each empty extent is allocated by using the fixeddata transfer rate Vout, which supports the optimum sound/image quality,a region thereof will be left unused after completion of the recordingof AV data. Accordingly, a region in the empty extent E₆ in which datahas been recorded becomes a real-time extent RT₆. If a region of an ECCblock is left without any AV data recorded therein, as may happen at theend of any given AV data to be recorded, such a region becomes an emptyextent 123. If one whole ECC block is left without any AV data recordedtherein, such an ECC block becomes an unused area 124 (Step S815).

[0192] In order to reinstate the unused area 124 as a recordable area,the file structure processing section 746 updates the data on the bitmap memory 756, and generates a file entry for the VIDEO.VRO file(composed of the real-time extents RT₁ to RT₆ and the empty extent 123)on the file structure memory 755. The data recording section 747instructs the optical disk drive 707 to record these space bit map andfile entry in predetermined positions. As a result, the space bit map141 and the file entry 148 as shown in FIG. 1 are recorded (Step S816).

[0193] Thus, as described above, predetermined parameters are setaccording to user instructions at Step S801; information concerningnon-contiguous areas on the optical disk is acquired from the opticaldisk drive 707 at Step S802; and areas from which data can becontinuously reproduced are finalized as empty extents at Steps S803 toS814. As a result, the optical disk drive 707, the control system, andthe application can be separately implemented. Therefore, the recordingmethod according to the present invention can be easily implemented in acomputer system in which an optical disk drive, a control system(including the operating system (OS)), and applications are separatelyprovided. Since steps S803 to S814 and step S816 can be realized byusing standard file system drivers which are provided in each OS, it ispossible to handle recording of general files and real-time files byusing standard file system drivers which are provided in each OS,thereby facilitating the development of application software forrecording/edition of video data.

[0194] Next, features of the information recording medium according tothe present invention will be described with reference to the playbackreference model illustrated in FIG. 2A and the real-time extentarrangement illustrated in FIG. 5C. Each real-time extent is composed ofa logically and physically contiguous area so that it is possible tocalculate any decrease in data amount within the buffer memory occurringresponsive to access by a pickup of the optical disk drive.

[0195] An increase (D(i)) in the amount of data having been stored inthe buffer memory responsive to the playback reference model reading thedata from an i^(th) real-time extent is:

D(i)=(Vin−Vout)×S(i)/Vin,

[0196] where S(i) represents the data size of an i^(th) real-timeextent; and

[0197] T(i) represents a time required for a pickup of the playbackreference model to access from the end of the i^(th) real-time extent tothe beginning of an (i+1)^(th) real-time extent.

[0198] The amount of data which is consumed from within the buffermemory when the playback reference model accesses from the end of thei^(th) real-time extent to the beginning of the (i+1)^(th) real-timeextent is—Vout×T(i).

[0199] Therefore, assuming that B(0)=0, the amount of data (B(i)) whichhas been stored in the buffer memory when the playback reference modelaccesses from the end of the i^(th) real-time extent to the beginning ofthe (i+1)^(th) real-time extent is:

B(i)=B(i−1)+D(i)−Vout×T(i).

[0200] Since the i^(th) real-time extent which was recorded by the aboverecording method is positioned so that a buffer overflow will not occur,D(i) is subjected to the following correction concerning overflowconditions.

When D(i)>Bmax−B(i−1),

D(i)=Bmax−B(i−1), or

D(i)=(Vin−Vout)×S(i)/Vin+B(i−1)−k×(Vout×Tk).

[0201] In the above equation, k represents an integer portion of((D(i)+B(i−1)−Bmax)/(Vout×Tk)+1).

[0202] In order to prevent a buffer underflow, the (i+1)^(th) real-timeextent is positioned at a position satisfying a real-time reproductioncondition defined as:

T(i)≦(B(i−1)+D(i))/Vout.

[0203] In other words, since the real-time extents RT₁ to RT₆ in FIG. 5Care positioned so as to satisfy the real-time reproduction conditiondefined above, it is possible for an actual reproduction apparatus whichsatisfies the performance of the playback reference model tocontinuously reproduce video data and audio data from this real-timeextent. In the determination as to whether the (i+1)^(th) pre-allocatedarea can be allocated as an empty extent in Steps S804 to S814, theaforementioned real-time reproduction condition can be conveniently usedto facilitate the determination.

[0204] Now, referring to FIGS. 7A, 7B, and 7C, attribute informationaccording to the present invention to be registered in the file entryfor real-time files (which has been recorded in Step S816) will bedescribed. FIG. 7A is a data structure diagram illustrating the fileentry for a real-time file. In the beginning of the file entry isrecorded a descriptor tag identifying this descriptor as a file entry.At byte position (hereinafter referred to as “BP”) 16 is recorded an ICBtag for recording attribute information of a real-time file. At BP 56 isrecorded the information length of the file body for identifying thefile body from the file tail. At BP 112 is recorded an extendedattribute ICB for recording location information for designating, in thecase where the extended attribute information (recorded at BP176)becomes too large to be recorded within the file entry, where to recordthe extended attribute information. At BP168 is recorded the length ofthe extended attribute recorded at BP176 (=L_EA). At BP172 is recordedthe entire length of an allocation descriptor which is recorded in bytepositions following L_EA. At BP176 is recorded an extended attribute. Inthe byte positions following L_EA is recorded an allocation descriptor.

[0205] In the byte positions following L_EA, short allocationdescriptors for real-time extents RT₁ to RT₆ and an empty extent 123 arerecorded. Real-time extents and empty extents are distinguished from oneanother based on the value(“0” and “1”, respectively) of the mostsignificant 2 bits of the extent length recorded at relative byteposition (hereinafter referred to as “RBP”) 0 of each short allocationdescriptor. Furthermore, the real-time extents RT₁ to RT₆ are recordedin the file main body, whereas the empty extent 123 is recorded in thefile tail.

[0206] At RBP1 of the ICB tag which is recorded in the file entry for areal-time file, a file type value “249” is recorded to indicate that thefile entry represents a real-time file. Based on the file type value, itcan be determined whether or not real-time data (which requirescontinuous reproduction) is recorded in the file. RBP18 of the ICB tagis a flag field, in which bit 4 indicates whether or not re-allocationis permitted. Bit 4 is set to “1” to indicate that the real-time extentsare positioned so as to satisfy the real-time reproduction conditionaccording to the present invention so far as this file is concerned. Bit4 is reset to “0” if the real-time files have been copied withoutconsidering the real-time reproduction condition, thereby providing ameans for indicating that the positioning of real-time extents is nolonger appropriate. This bit can also be utilized to prevent a utilitysuch as a defragmentation utility from undesirably changing thepositioning of real-time files.

[0207] In an extended attribute for allocation that is recorded in thefile entry for a real-time file, parameters used when allocating therespective extents of the real-time file are recorded. That is, a datatransfer rate Vin is recorded at RBP0; a data transfer rate Vout isrecorded at RBP2; a buffer memory size is recorded at RBP4; an accesstype for identifying each access performance type rate is recorded atRBP6; and access times are recorded at RBP8 and the subsequent relativebit positions. In the case of the access performance according to thepresent example, “1” is recorded as the access type, and the values ofTZ, TI, and TL are recorded as access times Ta, Tb, and Tc,respectively. In the case of the access performance of a DVD-R which isdescribed in Example 2, “2” is recorded as an access type.

[0208] Next, a method for reproducing real-time data from theinformation recording medium shown in FIG. 1 by using the informationrecording/reproduction apparatus according to one embodiment of thepresent invention, in accordance with the block structure illustrated inFIG. 3 and the flowchart illustrated in FIG. 8, will be described. Theoptical disk drive 707, which satisfies the access performance of theplayback reference model, is capable of reading data at a predetermineddata transfer rate Vin. The data buffer memory 757 has a size which isequal to or greater than that of the buffer memory 303 of the playbackreference model. Thus, the information recording/reproduction apparatussatisfies the predetermined performance of the playback reference model.

[0209] In the case where the information recording/reproductionapparatus has an access performance such that it is capable of fasteraccess than the predetermined access performance of the playbackreference model, it is possible to reduce the size of the data buffermemory 757 so as to be smaller than that of the buffer memory 303 of theplayback reference model.

[0210] The file structure processing section 746 instructs the data readsection 748 to read the volume structure area 104 and the file structurearea 105, and the data which is read by the optical disk drive 707 istransferred to the file structure memory 755 for analysis. Among thedata which has been read, the location information and attributeinformation of real-time extents are stored in the file structure memory755 (Step S901).

[0211] The file structure processing section 746 determines whether ornot this file is a real-time file based on the file type which isrecorded in the ICB tag shown in FIG. 7A, and confirms whether or notthe real-time extents are positioned so as to satisfy the real-timereproduction condition based on the non-relocatable bit (Step S902).

[0212] In the case where the file is a real-time file, the reproductionmode informing section 741 informs the allocation parameters which arerecorded in the extended attribute in the file entry to the optical diskdrive 707. Then, the optical disk drive 707 determines whether thereal-time file can be reproduced or not (Step S903).

[0213] The data read section 748 issues a reproduction command forreal-time data to the optical disk drive 707 (Step S904).

[0214] In accordance with the issued reproduction command, the opticaldisk drive 707 reads data from the real-time extents. During areproduction operation from real-time extents, the location informationof any defective sectors which have been subjected to a replacementprocess is ignored; and even if an error occurs during datareproduction, continuous data reproduction is performed withoutperforming any recovery process. The data which has been read istemporarily transferred to the data buffer memory 757, so that videodata and audio data are reproduced on the TV set via the decoder 711,which corresponds to the decoder module in the playback reference model(Step S905).

[0215] In the case where the file is a general file, the data readsection 748 issues a reproduction command for general data to theoptical disk drive 707 (Step S906).

[0216] In accordance with the issued reproduction command for generaldata, the optical disk drive 707 reads data. The data which has beenread is temporarily transferred to the data buffer memory 757,(StepS907).

[0217] Thus, the information recording/reproduction apparatus canreproduce the data continuously from real-time extents which arepositioned so as to satisfy the real-time reproduction condition,because the information recording/reproduction apparatus satisfies thepredetermined performance of the playback reference model.

[0218] Although the present example is directed to an optical disk ofthe ZCLV format, the present invention is also applicable to any DVD-RWdisk or hard disk whose defect management processing is handled by asystem controller. In the case of a DVD-RW, defect management isperformed based on a file system, and the location information of anysectors that are replaced by spare areas is managed based on a sparingtable. Therefore, at Step 802, it is possible to search for logicallyand physically contiguous unallocated areas from a space bit map.

[0219] Although the present example illustrates the case where the filestructure area is a single continuous region, the respective descriptorsmay be distributed throughout the disk without undermining the effectsof the present invention.

Example 2

[0220] Example 2 illustrates an instance in which new real-time data isappended to a real-time file which is already recorded on a DVD-R disk.

[0221] In the course of our description, the block structure of aninformation recording/reproduction apparatus shown in FIG. 9, and aplayback reference model and access performance in accordance with thisinformation recording/reproduction apparatus will be first describedwith reference to FIG. 10. Then, a method for appending data to areal-time file will be described with respect to an area structure shownin FIG. 13 and data amount transition within a buffer duringreproduction shown in FIG. 12. Next, a linking scheme for recording AVdata will be described with reference to FIG. 14. Then, the datastructure of the optical disk will be described with a focus on filemanagement information. Finally, a reproduction method will be describedwith reference to the flowchart shown in FIG. 8.

[0222]FIG. 9 is a block diagram illustrating an informationrecording/reproduction apparatus according to one embodiment of thepresent invention. The information recording/reproduction apparatusincludes a system controller 801, an I/O bus 806, an optical disk drive807, an input section 808 for inputting recording modes, etc., a tuner810 for receiving TV broadcast programs, an encoder 809 for encodingvideo/audio signals into AV data, and a decoder 811 for decoding the AVdata and outputting the decoded AV data to a TV set 812. In the case ofa personal computer, the respective sections in the system controller801 as shown in FIG. 9 may be implemented by a main CPU. Althoughdiscrete memories dedicated to different purposes are described, theymay be realized on one memory circuit. In the case of a video recorderwhich integrates the system controller 801 and the optical disk drive807, the various sections within the system controller 801 and theoptical disk drive 807 may be implemented by a single CPU.

[0223] The system controller 801 includes: a recording modedetermination section 802, an allocation parameter memory 803, a VOBU(video object unit) re-encoding section 821, a VOBU memory 822 forre-encoding VOBUs, a file system processing section 804, and a filesystem processing memory 805. In the case of a PC system, the recordingmode determination section 802 and the VOBU re-encoding section 821 maybe implemented by application software, and the file system processingsection 804 may be implemented by using standard file system driverswhich are provided in each OS.

[0224] The file system processing section 804 includes: an unrecordedarea check section 841, which in turn includes a linking setting section842 for designating a linking scheme and data recording start locations;a time information calculation section 843 for calculating timeinformation concerning reading of extents and access; a data amountcalculation section 844, which in turn includes a final access checksection 845 for calculating the presence or absence of a bufferunderflow during access to a data recordable area which is set within anunrecorded area; a file structure processing section 846; a datarecording section 847, which in turn includes a data copying section 848for copying already-recorded data to an unrecorded area in the casewhere a buffer underflow occurs; and a data read section 849, which inturn includes a reproduction mode informing section 850 for switchingbetween reproduction modes for AV data and non-AV data. The file systemprocessing memory 805, which is utilized by these sections includes afile structure memory 851, and a data memory 852, which also serves as abuffer memory.

[0225] The optical disk drive 807 includes: a data memory 871 fortemporarily storing data to be recorded or reproduced; a runoutcontroller 872 for controlling data to be recorded in a runout area; alinking controller 873 for controlling data append in a linking scheme;a data recorder 874 for controlling data recording; and a datareproducer 875 for controlling data reproduction. It is ensured that theaccess performance and the data recording rate of the optical disk drive807 and the size of the data buffer memory 852 are chosen so as toprovide a data recording performance which satisfies a level ofrecording performance that would be attained by using the playbackreference model for recording.

[0226]FIGS. 10A and 10B illustrate a playback reference model and itsaccess performance for determining conditions for positioning thereal-time data according to one embodiment of the present invention,respectively. The playback reference model illustrated in FIG. 10A isthe same playback reference model as that described in Example 1. Abuffer memory 303 and a decoder module 304 shown in FIG. 10A areimplemented as data the data memory 852 and the decoder 811,respectively.

[0227]FIG. 10B is a graph illustrating a relationship between accessdistances and access times during an access made to a DVD-R disk by apickup 302 in the playback reference model. It should be noted that, thegraph of FIG. 10B illustrates different access times from thoseillustrated in Example 1 (FIG. 2B), which was directed to a DVD-RAMdisk, because a different access performance is required of areproduction apparatus for DVD-R disk due to the physical structure ofthe disk medium. The access times are conveniently divided into fouraccess categories, depending on the access distance: skip access, shortaccess, middle access, and long access, although the actual accessperformance will present a non-linear profile. Any access occurring atthe ECC block level is defined as a skip access.

[0228] Next, in accordance with a flowchart shown in FIG. 11, arecording method will be described with respect to an area structureshown in FIG. 13 and data amount transition within a buffer duringreproduction shown in FIG. 12. The following example illustrates amethod for appending AV data to a real-time file which is composed ofreal-time extents RT₁ and RT₂ that have already been recorded. In orderto permit the appended AV data and the already-recorded AV data to bereproduced in a seamless manner, real-time extents are allocated underthe real-time reproduction condition as described in Example 1.

[0229] A recording mode and a recording time are designated via theinput section 808, which may be implemented as a remote control, amouse, or a keyboard. The recording mode determination section 802 firstdetermines whether the data to be recorded is AV data or not, andperforms the subsequent steps if the data to be recorded is AV data. Ifthe data to be recorded is AV data, the recording mode determinationsection 802 determines Vout, which defines a maximum data transfer rate;Vin, which defines a read rate from the disk; size SR of data to berecorded; a buffer size Bmax; and various access times, and store thesevalues in the allocation parameter memory 803 (Step S401: determinationof recording parameters).

[0230] The unrecorded area check section 841 acquires the size of anunrecorded area 553 (shown in FIG. 13A) from the optical disk drive 807to confirm that this size is sufficiently greater than the size of dataSR (=Vout×recording time) to be recorded. After the AV data, a fileentry for the real-time file to be updated and file managementinformation such as VAT ICB and VAT are recorded along with a linkingloss extent (32 KB). For example, when closing the disk, a border out isfurther recorded. Therefore, a sufficient data recordable area isrequired for the AV data to be recorded.

[0231] In order to realize a seamless reproduction between the file tailof a real-time file and the beginning of the appended AV data, the VOBUre-encoding section 821 reads the last VOBU in the last real-timeextent. The last VOBU is re-encoded by the encoder 809 so as to be ableto be recorded in the unrecorded area along with the new AV data. There-encoded VOBU is retained in the VOBU memory 822.

[0232] As used herein, a video object unit (VOBU) is MPEG data which iscomposed of a number of GOPs (group of pictures) within AV data whichhas been compressed in the MPEG format. Since MPEG data includes videoinformation and audio information that are recorded with a certain timeoffset, any appended AV data must be recorded while keeping this offsetintact in order to be able to be reproduced in a seamless manner.Accordingly, as described above, the last VOBU which has been read isre-encoded along with the new AV data to be recorded, and re-recorded inthe unrecorded area.

[0233] The file structure processing section 846 instructs the data readsection 849 to read the volume structure area and the file structurearea (described later), and the data which has been read by the opticaldisk drive 807 is analyzed on the file structure memory 851, whereby thelocations of all real-time extents (i.e., RT₁ and RT₂ in this example)in the real-time file are determined. At this time, real-time extentsRT_(i), except for the last extent, are allocated as pre-allocated areasA_(i) (i=1 to n−1; n is 2 in the example shown in FIG. 13), and theportion of the last real-time extent RT_(n) excluding the VOBU which hasbeen read is allocated as a pre-allocated area A_(n). Moreover, thelinking setting section 842 sets a linking loss extent 555 (describedlater) for the unrecorded area, while allocating the remainder as apre-allocated area A_(n+1).

[0234] In FIG. 13A, a linking loss extent 551 and an empty extent E₁ areareas which were formed when the real-time extent RT₁ was recorded.Similarly, a linking loss extent 552 and an empty extent E₂ are areaswhich were formed when the real-time extent RT₂ was recorded. An emptyextent is an area spanning between a sector in which data is recordedand an ECC block boundary. Reference numeral 554 represents an area inwhich the VOBU that has been read is recorded. Reference numeral 555represents a linking loss extent which is set within the unrecorded area553. The pre-allocated areas which are allocated during this step aredenoted as A₁, A₂, and A₃ (Step S402: check for unrecorded areas).

[0235] The time information calculation section 843 calculates a readtime TR_(i) (where i corresponds to the area number A_(i) forpre-allocated areas) required for reading each pre-allocated area at adata transfer rate of Vin (except for the last area) and an access timeT_(i,i+1) between pre-allocated areas (i.e., access time betweenpre-allocated areas A_(i) and A_(i+1)), by using the locationinformation of the pre-allocated areas and the various access timesretained in the allocation parameter memory 803. In FIG. 13B, the readtimes TR₁ and TR₂ are times required for reading the pre-allocated areasA₁ and A₂, respectively. Access times T_(1,2) and T_(2,3) are calculatedbased on the access performance shown in FIG. 10B, where access timeT_(m,n) represents an access time from the end of a pre-allocated areaA_(m) to the beginning of A_(n) (Step S403: calculation of read timeinformation and access time information).

[0236] Next, the data amount calculation section 844 performscalculation processes from Steps S404 to S414 for the pre-allocated areathat has been recorded, by using the read times and access timesobtained at Step S403. FIG. 12 shows a transition in the amount of datain the buffer memory responsive to reading of the pre-allocated areasand accesses (calculation of data amount in the buffer for each recordedarea).

[0237] First, the data amount (B(t)) in the buffer memory for thepre-allocated areas A₁ to A_(n) in which AV data has already beenrecorded is calculated in accordance with the following steps. It isassumed that t_(2i−2) and t_(2i−1) represent data read start time anddata read end time for an area A_(i), respectively (Step S404).

[0238] The data amount in the buffer memory at the data read start timefor an area A_(i) is calculated as follows (Step S405):

B(0)=0 (for A ₁)

B(t _(2i−2))=B(t _(2i−3))−(Vout×T _(i−1,1)) (for A ₂ and after).

[0239] The data amount in the buffer memory at the data read end timefor an area A_(i) is calculated as follows (Step S406):

B(t_(2i−1))=B(t _(2i−2))+(Vin−Vout)×TR _(i).

[0240] Next, it is checked whether or not the calculated data amountexceeds the buffer size Bmax

[0241] If overflow does not occur, the area for which to perform thecalculation is moved to a next area (Step S409), and the control returnsto Step S404 (Step S407).

[0242] If the calculation result indicates overflow, the optical diskdrive 807 temporarily suspends the data reproduction operation in orderto avoid overflow. Therefore, a minimum rotation wait time is added.Accordingly, the calculated data amount is corrected on the assumptionthat the data has decreased at a rate of Vout over a period of k×TK,where TK represents a rotation wait time at the outermost periphery ofthe information recording medium, and k=ip ((B(t)−Bmax)/(Vout×TK)+1)).B(t) represents a data amount when overflow occurs. Next, the area forwhich to perform the calculation is moved to a next area (Step S409),and the control returns to Step S404 (Step S408).

[0243] At time t₁ shown in FIG. 12, the data amount is correctedresponsive to an overflow.

[0244] Next, by using Steps S410 to S414, the final access check section845 calculates the data amount (B(t_(2n))) in the buffer memory at thedata read start time for the pre-allocated area A_(n+1) that has beenset in the unrecorded area (calculation of data amount in the buffer atthe beginning of the last pre-allocated area).

[0245] First, this data amount (B(t_(2n))) is calculated as follows(Step S410):

B(t _(2n))=B(t _(2n−1))−(Vout×T _(n,n−1))

[0246] At this time, data underflow is checked for. If underflow doesnot occur, the control proceeds to Step S415 (Step S411).

[0247] If underflow occurs, those pre-allocated areas which result in anon-zero (i.e., more than zero) data amount even when accessing to thelast pre-allocated are searched for, while excluding one after anotherpre-allocated area from this calculation from the outer periphery towardthe inner periphery of the disk, until an area in which underflow willnot occur. This search is performed as follows (Steps S412, S413, andS414): for i = 1 to n−1 { B(t_(2n)) = B(t_(2n−1−2i)) −(Vout×T_(n−1,n+1)). If B(t_(2n)) ≧ 0, A_(n+1) is updated to A_(n−j)*(where j = i−i); T_(n−1,n+1) is updated to T_(n−1,n−i+1)*; and thecontrol proceeds to Step S415 }.

[0248] In the example illustrated in FIGS. 12 and 13C, since a dataunderflow occurs at time t₄, the pre-allocated area A₂ is excluded fromthe above calculation. Accordingly, T_(1,3) is updated to T_(1,2)*, andA₃ is updated to A₂*, and the data amount after access from the end ofthe pre-allocated area A₁ to the beginning of A₂* is calculated. Nounderflow occurs when the pre-allocated area A₂ is excluded.

[0249] Next, the data copying section 848 copies the data recorded inthe pre-allocated area A₂, which was excluded from the abovecalculation, to the pre-allocated area A₂* (in a portion denoted as 557in FIG. 13D) so as to succeed the linking loss extent 555. The datarecording section 847 records the re-encoded VOBU (in a portion denotedas 558 in FIG. 13D) and the AV data to be appended (in a portion denotedas 559 in FIG. 13D)so as to succeed the data recorded in thepre-allocated area A₂. The regions 557, 558, and 559 become real-timeextents RT₂* (Step S415: recording of real-time data).

[0250] In the case where data is recorded to a DVD-R disk, the files arerecorded by using a VAT system which is defined under the UDFspecification. Therefore, a file structure associated therewith isrecorded in the unrecorded area 556 (Step S416: update of filestructure).

[0251] Thus, the arrangement of the real-time extents recorded in theaforementioned manner satisfy the real-time reproduction condition asdescribed in Example 1 of the present invention.

[0252] Next, recording of real-time extents will be described withrespect to the data structure of a linking scheme as shown in FIG. 14.The linking setting section 842 sets a linking loss extent 210 (32 KB),and records AV data. The linking loss extent 210 is composed of one ECCblock with 00h being recorded in all sectors. The first sector defines alinking sector. Since the linking loss extent 210 and the real-timeextent 211 are recorded so as to adjoin each other, no linking gap isformed at the boundary therebetween. As a result, the data reliabilityof the first sector is prevented from deteriorating.

[0253] Next, a recording method in the case where a buffer underrunoccurs between regions 212 and 213 will be described. A sector 215 is alinking sector. The specific data structure concerning sync frames isshown in FIG. 14D. Reference numerals 251, 252, 253, and 254 representareas which are recorded at an end portion when the area 212 isrecorded; 251 and 252 represent a sync portion and a data portion,respectively, of a first sync frame; and 253 and 254 represent a syncportion and a data portion, respectively, of a second sync frame.Reference numerals 255, 256, 257, and 258 represent areas which arerecorded at a beginning portion when the area 213 is recorded. Referencenumeral 255 represents a data portion in the second sync frame.Reference numerals 256, 257, and 258 represent sync portions in syncframes. The respective areas are sized as in the conventional exampledescribed earlier. Areas 216 and 217 are a runout area and a linkinggap, respectively.

[0254] The runout controller 872 of the optical disk drive 807 alwaysretains in the data memory 871 the data to be recorded to a next ECCblock. Therefore, if a buffer underrun occurs during data recording, thedata to be recorded in the runout area 216 is recorded, and therecording of the real-time extent 211 is temporarily suspended, andrecording of the area 212 is completed. At this time, the data to berecorded in the ECC block, including the linking sector, is retained inthe data memory 871. Next, when predetermined data is transferred fromthe system controller 801 to the data memory 871, the data recorder 874records the remaining linking sector data from the linking gap 217, andcontinues data recording.

[0255] Thus, since AV data (which requires continuity) is recorded incontiguous sectors, any waste of recordable areas due to linking lossareas can be prevented. Whereas the aforementioned conventional linkingscheme only permits 00h data to be recorded in the runout area, thelinking scheme according to the present example of the invention allowsactual data to be recorded in the runout area even in the presence of abuffer underrun. The portion in which data cannot be properly recordedis reduced to the few bytes which form as a linking gap. Therefore, evenif a linking gap is formed within a real-time extent, an errorcorrection based on ECC can be easily performed during datareproduction. Moreover, identification information is recorded in areasas illustrated in FIG. 14E, thereby making it possible for areproduction drive apparatus to easily distinguish thepreviously-recorded linking loss extents from real-time extents.

[0256] Each sector of a DVD disk includes regions for recording physicaladditional information, i.e., ID 261, IED 262, and CPR 263, in additionto a Main Data region 264 for recording 2048 bytes of user data. Thephysical information concerning the sector is recorded in ID 261. Anerror detection code for the ID section is recorded in IED 262. Copymanagement information is recorded in CPR 263. ID 261includes a sectorformat bit 265 and a data type bit 266. The sector format bit 265indicates whether the disk is in the CLV format or in the zone format.The data type bit 266 is a bit which is set to “1” in the case where anext sector is included within a linking loss extent, unless the sectoris a linking sector. As shown in FIG. 14B, the first sector in thelinking loss extent has a “0” data type bit because it is a linkingsector. The second to the 15th sector have a “1” data type bit becausethey belong in a linking loss extent.

[0257]FIG. 15 shows an exemplary data structure of an informationrecording medium in which files managed based on volume/file structuresunder the UDF specification are recorded. The arrangement of areas ineach real-time extent corresponds to that shown in FIG. 13. The upperportions in FIG. 15 correspond to the inner portions, and the lowerportions in FIG. 15 to the outer portions, of a DVD-R disk. A volumespace is defined as a region spanning from a volume structure area 152to an unrecorded area 171, in which files and volume/file structures arerecorded. From the inner periphery side, a lead-in area 151, a volumestructure area 152 and a file structure area 153 (which are recorded atthe time of formatting), and a linking loss extent 551, a real-timeextent RT₁, and an empty extent E₁ (which are formed at the time ofrecording AV data) are provided in this order.

[0258] Then, a FILEA.DAT file, which contains data of a plurality ofstill images obtained from a digital camera or the like, is recorded.Since still image data requires more reliability than real-timereproducibility, an extent 158 is recorded so as to succeed a linkingloss area 157, as in the case of general data. Furthermore, a filestructure area 159 for managing the recorded file is recorded so as tosucceed the extent 158. If AV data is to be recorded next, a linkingloss extent 552, a real-time extent RT₂ and an empty extent E₂ arerecorded. In order to ensure that this disk will be able to bereproduced by a read-only apparatus, a linking loss area 163 and a filestructure area 164 are recorded, and a border out (not shown) isrecorded within a border zone 165. In the case of appending AV data asdescribed with reference to FIGS. 13A to 13D, the VOBU 554 is read fromthe last region of the real-time extent RT₂, and the data recorded inthe remaining pre-allocated area A₂ is recorded in the copy area 557.The VOBU which has been read is re-encoded and recorded in the re-encodearea 558, and appended data is recorded in the added data area 559,which succeeds the re-encode area 558.

[0259] When recording the real-time extent RT₂*, the linking loss extent555 and the empty extent E₃ are recorded. If a buffer underrun occursduring the recording of the real-time extent RT₂*, a linking gap isformed, although not shown in FIG. 15. In the case of sequentialrecording media such as DVD-R disks and CD-R disks, the files aremanaged based on a VAT system which is defined under the UDFspecification. Therefore, a file structure area 170 is recorded at theend of the recorded area on the disk. The data recorded as describedabove has the same structure as that described with reference to FIG.17.

[0260] In the file structure area 170, a file entry 181 for a ROOTdirectory, a file entry 182 for a REALTIME directory, a file entry 183for a VIDEO.VRO file, a file entry 184 for the FILEA.DAT file, the ROOTdirectory 185, the REALTIME directory 186, a VAT 187, and a VAT ICB 188are recorded. The file entry 181 is management information for managingthe attribution information and the location information of the ROOTdirectory 185. As a ROOT directory file, a file identifier descriptor isrecorded, although not shown in FIG. 15. The file identifier descriptorincludes location information of the file entries 184 and 182 for theFILEA.DAT file and the REALTIME directory, which are created under theROOT directory 185.

[0261] The file entry 184 includes the location information of theextent 158 in which this file is recorded. The file entry 182 includesthe location information of the REALTIME directory file, which iscomposed of a file identifier descriptor. The file identifier descriptorincludes the location information of the file entry 183 for theVIDEO.VRO file, which is created under the REALTIME directory 186. Thefile entry 183 includes the location information of the real-timeextents RT₁ to RT₂* in which AV data is recorded.

[0262] The attribute information which is recorded in the file entry fora real-time file is the same as that described in Example 1 withreference to FIGS. 7A to 7C. However, in the case of a DVD-R disk, it isunnecessary to register empty extents in real-time files because a DVD-Rdisk has no defective management mechanism associated therewith.

[0263] Next, a method for reproducing AV data from the informationrecording medium illustrated in FIG. 15 in accordance with the blockstructure illustrated in FIG. 9 and the flowchart illustrated in FIG. 8will be described. The reproduction method is the same as that describedin Example 1. The optical disk drive 807, which satisfies the accessperformance of the playback reference model, is capable of reading dataat a predetermined data transfer rate Vin. The data buffer memory 852has a size which is equal to or greater than that of the buffer memory303 of the playback reference model.

[0264] The file structure processing section 846 causes the volumestructure area 152 and the file structure area 170 to be read to thefile structure memory 851 for analysis. Among the data which has beenread, the location information and attribute information of real-timeextents are stored in the file structure memory 851 (Step S901).

[0265] The file structure processing section 846 determines whether ornot this file is a real-time file, and confirms whether or not thereal-time extents are positioned so as to satisfy the real-timereproduction condition (Step S902).

[0266] In the case where the file is a real-time file, the reproductionmode informing section 850 informs the allocation parameters which arestored in the allocation parameter memory 803 to the optical disk drive807 (Step S903). The data read section 849 issues a reproduction commandfor AV data to the optical disk drive 807 (Step S904).

[0267] In accordance with the reproduction command issued at Step S904,the optical disk drive 807 reads AV data from the real-time extents RT₁and RT₂*. Even if an error occurs during data reproduction due toreproduction from a linking gap, continuous data reproduction isperformed without performing any recovery process. The data which hasbeen read is subjected to ECC processing, temporarily transferred to thedata buffer memory 852, so that video data and audio data are reproducedon the TV set 812 via the decoder 811 (Step S905).

[0268] In the case where the file is a general file, the data readsection 849 issues a reproduction command for general data to theoptical disk drive 807 (Step S906).

[0269] In accordance with the issued reproduction command for generaldata, the optical disk drive 807 reads data. The data which has beenread is temporarily transferred to the data buffer memory 852 (StepS907).

[0270] It will be appreciated that the recording method according to thepresent example of the invention, which involves copying a recorded areato an unrecorded area and re-encoding VOBUs in order to allocatepre-allocated areas so that the playback reference model will notexperience a buffer underflow when reproducing a real-time file, can beapplied not only to write-once optical disks but also rewritable opticaldisks.

[0271] In the case where the recording method according to the presentinvention is applied to a rewritable optical disk, a plurality ofunallocated areas are searched for at Step S402 shown in FIG. 11. Inthat case, the recording method described in Example 2 is applied to thelast real-time extent of a previously-recorded real-time file and thefirst real-time extent that is newly-allocated; and the recording methoddescribed in Example 1 is applied to the selection as to which one ofthe plurality of newly-searched areas should be selected.

[0272] Although FIG. 10B illustrates an example in which the accessperformance for a DVD-R disk is defined based on four categories ofaccess distances, the transition in data amount with the buffer can bemore accurately calculated by defining the access performance based one.g., five or six access distance categories.

[0273] Although AV data which has been compressed in the MPEG format isillustrated above, it will be appreciated that the effects of thepresent invention can also be attained when applied to non-compressed,high quality audio data that has been subjected to high-sampling, ortransport streams which are transferred via digital TV broadcasting.

[0274] Although the above examples illustrated linking loss extentswhich are sized at 32 KB, they may alternatively sized at 2 KB. In thiscase, the first sector of an ECC block will be a linking loss extent,whereas the other 15 sectors can be used for recording data, so that thedata recording efficiency will be improved by 15 sectors. However, theerror correction ability for data within each ECC block will becorrespondingly reduced.

[0275] It will be appreciated that the present invention is alsoapplicable to a DVD-RW, in which a linking gap within a linking sectoris positioned at the 15th byte to the 17th byte in a first sync frame,and a runout area is composed of a sync portion in the first sync frameand 16 bytes of a data portion. In particular, by recording a linkingloss extent prior to the recording of real-time data, it will bepossible to secure the reliability of the first data of each real-timeextent, and continuous data recording/reproduction abilities can berealized by forming a linking gap within the real-time extent, whileminimizing the deterioration in data reliability.

[0276] The above examples illustrates instances where real-time data isrecorded in a runout area which is positioned within a real-time extent.However, it is possible to provide a simplified optical disk drive byrecording 00h data in a runout area without implementing this particularfunction. Although data reliability within each linking loss extent willdeteriorate, it is still possible to continuously record real-time data.

[0277] Although FIG. 15 illustrates the case where the linking lossextent 555 is positioned outside the border zone 165, it will beappreciated that the effects of the present invention can also beattained in the case where the linking loss extent 555 is recorded in aportion of the border zone 165.

[0278] Thus, according to the present invention, it is possible toprovide an information recording medium which permits continuousreproduction of real-time data carried on a recordable optical disk; arecording method and a reproduction method for such an informationrecording medium; and an information recording apparatus and aninformation reproduction apparatus for such an information recordingmedium.

[0279] Various other modifications will be apparent to and can bereadily made by those skilled in the art without departing from thescope and spirit of this invention. Accordingly, it is not intended thatthe scope of the claims appended hereto be limited to the description asset forth herein, but rather that the claims be broadly construed.

What is claimed is:
 1. An information recording medium for recording areal-time file containing real-time data in such a manner that thereal-time data is continuously reproducible by a playback referencemodel, the real-time data comprising at least one of video data andaudio data, wherein the playback reference model includes: a pickup forreading the real-time data from the information recording medium; abuffer memory for temporarily storing the real-time data read by thepickup; and a decoder module for reading the real-time data from thebuffer memory for processing, wherein the information recording mediumcomprises a volume space for at least recording in sectors a filecomprising data and file management information for managing the file;the real-time data is recorded in at least two real-time extents each ofwhich is allocated in logically contiguous sectors within the volumespace; and an (i+1)^(th) real-time extent among the at least tworeal-time extents is positioned at a position satisfying a real-timereproduction condition defined as: T(i)≦(B(i−1)+D(i))/Vout,  wherein:T(i) represents a time required for the pickup to access from an end ofan i^(th) real-time extent among the at least two real-time extents to abeginning of the (i+1)^(th) real-time extent; B(i) represents an amountof data having been stored in the buffer memory when the pickup accessesfrom the end of the i^(th) real-time extent to the beginning of the(i+1)^(th) real-time extent, such that B(i)=B(i−1)+D(i)−Vout×T(i),assuming that B(0)=0, D(i) represents an increase in the amount of datahaving been stored in the buffer memory responsive to the pickup readingthe data from the i^(th) real-time extent, such thatD(i)=(Vin−Vout)×S(i)/Vin, wherein D(i) is corrected at least to a valueequal to or smaller than M−B(i−1) when D(i)>M−B(i−1), where M representsa size of the buffer memory; Vout represents a data transfer rate whenthe data is transferred from the buffer memory to the decoder module;Vin represents a data transfer rate when the data is read from each ofthe at least two real-time extents by the pickup and transferred to thebuffer memory; and S(i) represents a data size of the i^(th) real-timeextent.
 2. An information recording medium according to claim 1, whereinD(i) is corrected so that D(i)=(Vin−Vout)×S(i)/Vin+B (i−1)−k×(Vout×Tk)when D(i)>M−B(i−1), wherein: Tk represents a maximum rotation wait timeof the information recording medium; and k represents an integer portionof ((D(i)+B(i−1)−M)/(Vout×Tk)+1).
 3. An information recording mediumaccording to claim 1, wherein each of the at least two real-time extentsis allocated in physically contiguous sectors.
 4. An informationrecording medium according to claim 1, wherein the file managementinformation comprises location information indicating each of the atleast two real-time extents.
 5. An information recording mediumaccording to claim 1, wherein the file management information comprisesfirst identification information for identifying the real-time fileincluding real-time data.
 6. An information recording medium accordingto claim 1, wherein the file management information comprises secondidentification information for indicating that the at least tworeal-time extents are positioned in accordance with the real-timereproduction condition.
 7. An information recording medium according toclaim 1, wherein the file management information comprises, as anextended attribute, information representing a condition under which theat least two real-time extents were positioned.
 8. An informationrecording medium for recording a real-time file containing real-timedata in such a manner that the real-time data is continuouslyreproducible by a playback reference model, the real-time datacomprising at least one of video data and audio data, wherein theplayback reference model includes: a pickup for reading the real-timedata from the information recording medium; a buffer memory fortemporarily storing the real-time data read by the pickup; and a decodermodule for reading the real-time data from the buffer memory forprocessing, wherein the information recording medium comprises a volumespace for at least recording in sectors a file comprising data and filemanagement information for managing the file; the real-time data isrecorded in at least two real-time extents each of which is allocated inlogically contiguous sectors within the volume space; and an (i+1)^(th)real-time extent among the at least two real-time extents is positionedat a position satisfying a real-time reproduction condition defined as:T(i)≦(B(i−1)+D(i))/Vout,  wherein: T(i) represents a time required forthe pickup to access from an end of an i^(th) real-time extent among theat least two real-time extents to a beginning of the (i+1)^(th)real-time extent; B(i) represents an amount of data having been storedin the buffer memory when the pickup accesses from the end of the i^(th)real-time extent to the beginning of the (i+1)^(th) real-time extent,such that B(i)=B(i−1)+D(i)−Vout×T(i), assuming that B(0)=0, D(i)represents an increase in the amount of data having been stored in thebuffer memory responsive to the pickup reading the data from the i^(th)real-time extent, such that D(i)=(Vin−Vout)×S(i)/Vin, wherein D(i) iscorrected at least to a value equal to or smaller than M−B(i−1) whenD(i)>M−B(i−1), where M represents a size of the buffer memory; Voutrepresents a data transfer rate when the data is transferred from thebuffer memory to the decoder module; Vin represents a data transfer ratewhen the data is read from each of the at least two real-time extents bythe pickup and transferred to the buffer memory; and S(i) represents adata size of the i^(th) real-time extent, wherein the real-time file isa file in which the real-time data is appended; and wherein data of analready recorded real-time extent is recorded in a newly recordedreal-time extent.
 9. An information recording medium according to claim8, wherein D(i) is corrected so thatD(i)=(Vin−Vout)×S(i)/Vin+B(i−1)−k×(Vout×Tk) when D(i)>M−B(i−1), wherein:Tk represents a maximum rotation wait time of the information recordingmedium; and k represents an integer portion of((D(i)+B(i−1)−M)/(Vout×Tk)+1).
 10. An information recording mediumaccording to claim 8, wherein each of the at least two real-time extentsis allocated in physically contiguous sectors.
 11. An informationrecording medium according to claim 8, wherein the file managementinformation comprises location information indicating each of the atleast two real-time extents.
 12. An information recording mediumaccording to claim 8, wherein the file management information comprisesfirst identification information for identifying the real-time fileincluding real-time data.
 13. An information recording medium accordingto claim 8, wherein the file management information comprises secondidentification information for indicating that the at least tworeal-time extents are positioned in accordance with the real-timereproduction condition.
 14. An information recording medium according toclaim 8, wherein the file management information comprises, as anextended attribute, information representing a condition under which theat least two real-time extents were positioned.
 15. An informationrecording medium for recording a real-time file containing real-timedata in such a manner that the real-time data is continuouslyreproducible by a playback reference model, the real-time datacomprising at least one of video data and audio data, wherein theplayback reference model includes: a pickup for reading the real-timedata from the information recording medium; a buffer memory fortemporarily storing the real-time data read by the pickup; and a decodermodule for reading the real-time data from the buffer memory forprocessing, wherein the information recording medium comprises a volumespace for at least recording in sectors a file comprising data and filemanagement information for managing the file; the real-time data isrecorded in at least two real-time extents each of which is allocated inlogically contiguous sectors within the volume space; and an (i+1)^(th)real-time extent among the at least two real-time extents is positionedat a position satisfying a real-time reproduction condition defined as:T(i)≦(B(i−1)+D(i))/Vout,  wherein: T(i) represents a time required forthe pickup to access from an end of an i^(th) real-time extent among theat least two real-time extents to a beginning of the (i+1)^(th)real-time extent; B(i) represents an amount of data having been storedin the buffer memory when the pickup accesses from the end of the i^(th)real-time extent to the beginning of the (i+1)^(th) real-time extent,such that B(i)=B(i−1)+D(i)−Vout×T(i), assuming that B(0)=0, D(i)represents an increase in the amount of data having been stored in thebuffer memory responsive to the pickup reading the data from the i^(th)real-time extent, such that D(i)=(Vin−Vout)×S(i)/Vin, wherein D(i) iscorrected at least to a value equal to or smaller than M−B(i−1) whenD(i)>M−B(i−1), where M represents a size of the buffer memory; Voutrepresents a data transfer rate when the data is transferred from thebuffer memory to the decoder module; Vin represents a data transfer ratewhen the data is read from each of the at least two real-time extents bythe pickup and transferred to the buffer memory; and S(i) represents adata size of the i^(th) real-time extent, wherein the real-time file isa file in which the real-time data is appended; wherein the real-timedata is compressed in an MPEG format; and wherein data comprising one ormore GOPs recorded at an end of the real-time file before appending isre-encoded and is recorded in a newly recorded real-time extent.
 16. Aninformation recording medium according to claim 15, wherein D(i) iscorrected so that D(i)=(Vin−Vout)×S(i)/Vin+B(i−1)−k×(Vout×Tk) whenD(i)>M−B(i−1), wherein: Tk represents a maximum rotation wait time ofthe information recording medium; and k represents an integer portion of((D(i)+B(i−1)−M)/(Vout×Tk)+1).
 17. An information recording mediumaccording to claim 15, wherein each of the at least two real-timeextents is allocated in physically contiguous sectors.
 18. Aninformation recording medium according to claim 15, wherein the filemanagement information comprises location information indicating each ofthe at least two real-time extents.
 19. An information recording mediumaccording to claim 15, wherein the file management information comprisesfirst identification information for identifying the real-time fileincluding real-time data.
 20. An information recording medium accordingto claim 15, wherein the file management information comprises secondidentification information for indicating that the at least tworeal-time extents are positioned in accordance with the real-timereproduction condition.
 21. An information recording medium according toclaim 15, wherein the file management information comprises, as anextended attribute, information representing a condition under which theat least two real-time extents were positioned.
 22. An informationrecording medium comprising a volume space for at least recording insectors a file comprising data and file management information formanaging the file, wherein: the data comprises real-time data, thereal-time data comprising at least one of video data and audio data; thereal-time data is recorded in at least one real-time extent each ofwhich is allocated in logically contiguous sectors within the volumespace; the file comprises at least one real-time extent; a linking lossextent is positioned before each of the at least one real-time extent;and a linking gap is formed in the at least one real-time extent.
 23. Aninformation recording medium according to claim 22, wherein the linkingloss extent comprises one ECC block.
 24. An information recording mediumaccording to claim 22, wherein the file management information compriseslocation information indicating each of the at least one real-timeextent.
 25. An information recording medium according to claim 22,wherein the file management information comprises identificationinformation for identifying the real-time file including real-time data.26. An information recording medium according to claim 22, wherein adata type bit is recorded in an area f or recording physical additionalinformation concerning each sector within the linking loss extent, thedata type bit being used for identifying the linking loss extent; andwherein the data type bit for the sector is set to 1 if a next sector isincluded within the linking loss extent, unless the sector is a linkingsector.
 27. An information recording medium according to cl aim 22,wherein a runout area is formed before the linking gap; and thereal-time data is recorded in the runout area within the linking lossextent.
 28. A method for recording a real-time file containing real-timedata on an information recording medium in such a manner that thereal-time data is continuously reproducible by a playback referencemodel, the real-time data comprising at least one of video data andaudio data, wherein the playback reference model includes: a pickup forreading the real-time data from the information recording medium; abuffer memory for temporarily storing the real-time data read by thepickup; and a decoder module for reading the real-time data from thebuffer memory for processing, wherein the information recording mediumcomprises a volume space for at least recording in sectors a filecomprising data and file management information for managing the file,the real-time data is recorded in at least one real-time extent each ofwhich is allocated in logically contiguous sectors within the volumespace, wherein the method comprises the steps of: searching for at leasttwo areas satisfying a real-time reproduction condition from among aplurality of logically contiguous unused areas within the volume space,each of the at least two areas being designated as a pre-allocated area,an (i+1)th pre-allocated area among the at least two areas satisfyingthe real-time reproduction condition being defined as:T(i)≦(B(i−1)+D(i))/Vout,  wherein: T(i) represents a time required forthe pickup to access from an end of an i^(th) pre-allocated area amongthe at least two pre-allocated areas to a beginning of the (i+1)^(th)pre-allocated area; B(i) represents an amount of data having been storedin the buffer memory when the pickup accesses from the end of the i^(th)pre-allocated area to the beginning of the (i+1)^(th) pre-allocatedarea, such that B(i)=B(i−1)+D(i)−Vout×T(i), assuming that B(0)=0, D(i)represents an increase in the amount of data having been stored in thebuffer memory responsive to the pickup reading the data from the i^(th)pre-allocated area, such that D(i)=(Vin−Vout)×S(i)/Vin, wherein D(i) iscorrected at least to a value equal to or smaller than M−B(i−1) whenD(i)>M−B(i−1), where M represents a size of the buffer memory; Voutrepresents a data transfer rate when the data is transferred from thebuffer memory to the decoder module; Vin represents a data transfer ratewhen the data is read from the pre-allocated area by the pickup andtransferred to the buffer memory; and S(i) represents a data size of thei^(th) pre-allocated area; recording the real-time data in thepre-allocated area; designating a set of logically contiguous sectors inwhich real-time data is recorded as a real-time extent; and recordingthe file management information for managing the real-time data as thereal-time file.
 29. A method according to claim 28, wherein D(i) iscorrected so that D(i)=(Vin−Vout)×S(i)/Vin+B(i−1)−k×(Vout×Tk) whenD(i)>M−B(i−1), wherein: Tk represents a maximum rotation wait time ofthe information recording medium; and k represents an integer portion of((D(i)+B(i−1)−M)/(Vout×Tk)+1).
 30. A method according to claim 28,wherein each of the at least one pre-allocated area is allocated inphysically contiguous sectors on an ECC block-by-ECC block basis.
 31. Amethod according to claim 28, wherein the file management informationcomprises location information indicating each of the at least tworeal-time extents.
 32. A method according to claim 28, wherein the filemanagement information comprises first identification information foridentifying the real-time file including real-time data.
 33. A methodaccording to claim 28, wherein the file management information comprisessecond identification information for indicating that the at least tworeal-time extents are positioned in accordance with the real-timereproduction condition.
 34. A method according to claim 28, wherein thefile management information comprises, as an extended attribute,information representing a condition under which the at least tworeal-time extents were positioned.
 35. A method for recording areal-time file containing real-time data on an information recordingmedium in such a manner that the real-time data is continuouslyreproducible by a playback reference model, the real-time datacomprising at least one of video data and audio data, wherein theplayback reference model includes: a pickup for reading the real-timedata from the information recording medium; a buffer memory fortemporarily storing the real-time data read by the pickup; and a decodermodule for reading the real-time data from the buffer memory forprocessing, wherein the information recording medium comprises a volumespace for at least recording in sectors a file comprising data and filemanagement information for managing the file, the real-time data isrecorded in at least one real-time extent each of which is allocated inlogically contiguous sectors within the volume space, wherein the methodcomprises the steps of: calculating whether or not each of the at leastone real-time extent will cause an overflow in an amount of data storedin the buffer memory if the real-time extent is reproduced by theplayback reference model; when it is calculated that the real-timeextent will cause an overflow, correcting the amount of data stored inthe buffer memory to equal to or smaller than the size of the buffermemory; calculating whether or not an underflow will occur in the amountof data stored in the buffer memory if the playback reference modelaccesses from the real-time extent to a newly-allocated pre-allocatedarea; when it is calculated that an underflow will occur, searching fora real-time extent which will not cause an underflow, on accessing fromthe real-time extent to the pre-allocated area; recording in thenewly-allocated pre-allocated area the real-time data already recordedin the real-time extent which will cause an underflow; recordingreal-time data to be appended in the newly-allocated pre-allocated area;designating a set of logically contiguous sectors in which real-timedata is recorded as a real-time extent; and recording the filemanagement information.
 36. A method according to claim 35, wherein eachof the at least one pre-allocated area is allocated in physicallycontiguous sectors on an ECC block-by-ECC block basis.
 37. A methodaccording to claim 35, wherein the file management information compriseslocation information indicating each of the at least one real-timeextent.
 38. A method according to claim 35, wherein the file managementinformation comprises first identification information for identifyingthe real-time file including real-time data.
 39. A method according toclaim 35, wherein the file management information comprises secondidentification information for indicating that the at least tworeal-time extents are positioned in accordance with the real-timereproduction condition.
 40. A method according to claim 35, wherein thefile management information comprises, as an extended attribute,information representing a condition under which the at least tworeal-time extent were positioned.
 41. A method for appending a real-timefile containing real-time data on an information recording medium insuch a manner that the real-time data is continuously reproducible by aplayback reference model, the real-time data comprising at least one ofvideo data and audio data, wherein the playback reference modelincludes: a pickup for reading the real-time data from the informationrecording medium; a buffer memory for temporarily storing the real-timedata read by the pickup; and a decoder module for reading the real-timedata from the buffer memory for processing, wherein the informationrecording medium comprises a volume space for at least recording insectors a file comprising data and file management information formanaging the file, the real-time data is recorded in at least onereal-time extent each of which is allocated in logically contiguoussectors within the volume space, wherein the real-time file comprisesdata which is compressed in an MPEG format, wherein the method comprisesthe steps of: reading data recorded at an end of the real-time filebefore appending, the data comprising one or more GOPs; re-encoding thedata which has been read; recording the re-encoded data in a newlyallocated pre-allocated area; recording real-time data to be appended inthe newly-allocated pre-allocated area; designating a set of logicallycontiguous sectors in which real-time data is recorded as a real-timeextent; and recording the file management information.
 42. A methodaccording to claim 41, wherein each of the at least one pre-allocatedarea is allocated in physically contiguous sectors on an ECCblock-by-ECC block basis.
 43. A method according to claim 41, whereinthe file management information comprises location informationindicating each of the at least one real-time extent.
 44. A methodaccording to claim 41, wherein the file management information comprisesfirst identification information for identifying the real-time fileincluding real-time data.
 45. A method according to claim 41, whereinthe file management information comprises second identificationinformation for indicating that the at least two real-time extents arepositioned in accordance with the real-time reproduction condition. 46.A method according to claim 41, wherein the file management informationcomprises, as an extended attribute, information representing acondition under which the at least two real-time extents werepositioned.
 47. A method for recording information on an informationrecording medium comprising a volume space for at least recording insectors a file comprising data and file management information formanaging the file, comprising the steps of: determining whether or notthe file is a real-time file containing real-time data; recording thefile management information in the volume space; recording the real-timedata next to a linking loss extent if the file is determined to be areal-time file; and responsive to a buffer underrun occurring during therecording of the real-time data, forming a linking gap in a real-timeextent in which the real-time data is recorded.
 48. A method accordingto claim 47, wherein the linking loss extent comprises one ECC block.49. A method according to claim 47, wherein the file managementinformation comprises location information indicating each real-timeextent.
 50. A method according to claim 47, wherein the file managementinformation comprises identification information for identifying thereal-time file including real-time data.
 51. A method according to claim47, wherein a data type bit is recorded in an area for recordingphysical additional information concerning each sector within thelinking loss extent, the data type bit being used for identifying thelinking loss extent; and wherein the data type bit for the sector is setto 1 if a next sector is included within the linking loss extent, unlessthe sector is a linking sector.
 52. A method according to claim 47,further comprising a step of recording the real-time data in a runoutarea within the linking loss extent.
 53. An information recordingapparatus for recording a real-time file containing real-time data on aninformation recording medium in such a manner that the real-time data iscontinuously reproducible by a playback reference model, the real-timedata comprising at least one of video data and audio data, wherein theplayback reference model includes: a pickup for reading the real-timedata from the information recording medium; a buffer memory fortemporarily storing the real-time data read by the pickup; and a decodermodule for reading the real-time data from the buffer memory forprocessing, wherein the information recording medium comprises a volumespace for at least recording in sectors a file comprising data and filemanagement information for managing the file; wherein the informationrecording apparatus comprises a file system processing section for:allocating at least two areas satisfying a real-time reproductioncondition from among a plurality of logically contiguous unused areaswithin the volume space, each of the at least two areas being designatedas a pre-allocated area; recording the real-time data and the filemanagement information; designating a set of logically contiguoussectors in which real-time data is recorded as a real-time extent; andgenerating the file management information for managing the real-timedata as the real-time file, wherein an (i+1)^(th) pre-allocated areaamong the at least two pre-allocated areas is positioned at a positionsatisfying a real-time reproduction condition defined as:T(i)≦(B(i−1)+D(i))/Vout,  wherein: T(i) represents a time required forthe pickup to access from an end of an i^(th) pre-allocated area amongthe at least two pre-allocated areas to a beginning of an (i+1)^(th)pre-allocated area among the at least two pre-allocated areas: B(i)represents an amount of data having been stored in the buffer memorywhen the pickup accesses from the end of the i^(th) pre-allocated areato the beginning of the (i+1)^(th) pre-allocated area, such thatB(i)=B(i−1)+D(i)−Vout×T(i), assuming that B(0)=0, D(i) represents anincrease in the amount of data having been stored in the buffer memoryresponsive to the pickup reading the data from the i^(th) pre-allocatedarea, such that D(i)=(Vin−Vout)×S(i)/Vin, wherein D(i) is corrected atleast to a value equal to or smaller than M−B(i−1) when D(i)>M−B(i−1),where M represents a size of the buffer memory; Vout represents a datatransfer rate when the data is transferred from the buffer memory to thedecoder module; Vin represents a data transfer rate when the data isread from the pre-allocated area by the pickup and transferred to thebuffer memory; and S(i) represents a data size of the i^(th)pre-allocated area.
 54. An information recording apparatus according toclaim 53, wherein D(i) is corrected so thatD(i)=(Vin−Vout)×S(i)/Vin+B(i−1)−k×(Vout×Tk) when D(i)>M−B(i−1), wherein:Tk represents a maximum rotation wait time of the information recordingmedium; and k represents an integer portion of((D(i)+B(i−1)−M)/(Vout×Tk)+1).
 55. An information recording apparatusaccording to claim 53, wherein each of the at least one pre-allocatedarea is allocated in physically contiguous sectors on an ECCblock-by-ECC block basis.
 56. An information recording apparatusaccording to claim 53, wherein the file management information compriseslocation information indicating each real-time extent.
 57. Aninformation recording apparatus according to claim 53, wherein the filemanagement information comprises first identification information foridentifying the real-time file including real-time data.
 58. Aninformation recording apparatus according to claim 53, wherein the filemanagement information comprises second identification information forindicating that the at least two real-time extents are positioned inaccordance with the real-time reproduction condition.
 59. An informationrecording apparatus according to claim 53, wherein the file managementinformation comprises, as an extended attribute, informationrepresenting a condition under which the at least two real-time extentswere positioned.
 60. An information recording apparatus for appending areal-time file containing real-time data on an information recordingmedium in such a manner that the real-time data is continuouslyreproducible by a playback reference model, the real-time datacomprising at least one of video data and audio data, wherein theplayback reference model includes: a pickup for reading the real-timedata from the information recording medium; a buffer memory fortemporarily storing the real-time data read by the pickup; and a decodermodule for reading the real-time data from the buffer memory forprocessing, wherein the information recording medium comprises a volumespace for at least recording in sectors a file comprising data and filemanagement information for managing the file, the real-time data isrecorded in at least one real-time extent each of which is allocated inlogically contiguous sectors within the volume space, wherein theinformation recording apparatus comprises: a data amount calculationsection for calculating whether or not each of the at least onereal-time extent will cause an overflow in an amount of data stored inthe buffer memory if the real-time extent is reproduced by the playbackreference model; correcting the amount of data stored in the buffermemory to equal to or smaller than the size of the buffer memory when itis calculated that the real-time extent will cause an overflow;calculating whether or not an underflow will occur in the amount of datastored in the buffer memory if the playback reference model accessesfrom the real-time extent to a newly-allocated pre-allocated area; andsearching for a real-time extent which will not cause an underflow, onaccessing from the real-time extent to the pre-allocated area when it iscalculated that an underflow will occur; a data recording section forrecording in the newly allocated pre-allocated area the real-time dataalready recorded in the real-time extent which will cause an underflow,and recording real-time data to be appended in the newly-allocatedpre-allocated area; and a file structure processing section fordesignating a set of logically contiguous sectors in which real-timedata is recorded as a real-time extent and for generating and recordingthe file management information.
 61. An information recording apparatusaccording to claim 60, wherein each of the at least one pre-allocatedarea is allocated in physically contiguous sectors on an ECCblock-by-ECC block basis.
 62. An information recording apparatusaccording to claim 60, wherein the file management information compriseslocation information indicating each of the at least one real-timeextent.
 63. An information recording apparatus according to claim 60,wherein the file management information comprises first identificationinformation for identifying the real-time file including real-time data.64. An information recording apparatus according to claim 60, whereinthe file management information comprises second identificationinformation for indicating that the at least two real-time extents arepositioned in accordance with the real-time reproduction condition. 65.An information recording apparatus according to claim 60, wherein thefile management information comprises, as an extended attribute,information representing a condition under which the at least tworeal-time extents were positioned.
 66. An information recordingapparatus for appending a real-time file containing real-time data on aninformation recording medium in such a manner that the real-time data iscontinuously reproducible by a playback reference model, the real-timedata comprising at least one of video data and audio data, wherein theplayback reference model includes: a pickup for reading the real-timedata from the information recording medium; a buffer memory fortemporarily storing the real-time data read by the pickup; and a decodermodule for reading the real-time data from the buffer memory forprocessing, wherein the information recording medium comprises a volumespace for at least recording in sectors a file comprising data and filemanagement information for managing the file, the real-time data isrecorded in at least one real-time extent each of which is allocated inlogically contiguous sectors within the volume space, wherein thereal-time file comprises data which is compressed in an MPEG format,wherein the information recording apparatus comprises: a re-encodingsection for reading data recorded at an end of the real-time file beforeappending, the data comprising one or more GOPs, re-encoding the datawhich has been read, and recording the re-encoded data in a newlyallocated pre-allocated area; and a file structure processing sectionfor designating a set of logically contiguous sectors in which real-timedata is recorded as a real-time extent and for generating and recordingthe file management information.
 67. An information recording apparatusaccording to claim 66, wherein each of the at least one pre-allocatedarea is allocated in physically contiguous sectors on an ECCblock-by-ECC block basis.
 68. An information recording apparatusaccording to claim 66, wherein the file management information compriseslocation information indicating each of the at least two real-timeextents.
 69. An information recording apparatus according to claim 66,wherein the file management information comprises first identificationinformation for identifying the real-time file including real-time data.70. An information recording apparatus according to claim 66, whereinthe file management information comprises second identificationinformation for indicating that the at least two real-time extents arepositioned in accordance with the real-time reproduction condition. 71.An information recording apparatus according to claim 66, wherein thefile management information comprises, as an extended attribute,information representing a condition under which the at least tworeal-time extents were positioned.
 72. An information recordingapparatus for recording information on an information recording mediumcomprising a volume space for at least recording in sectors a filecomprising data and file management information for managing the file,comprising: a recording mode determination section for determiningwhether or not the file is a real-time file containing real-time data; afile structure processing section for recording the file managementinformation in the volume space; a linking setting section for recordingthe real-time data next to a linking loss extent if the file isdetermined to be a real-time file; and a linking controller for,responsive to a buffer underrun occurring during the recording of thereal-time data, forming a linking gap in a real-time extent in which thereal-time data is recorded.
 73. An information recording apparatusaccording to claim 72, wherein the linking loss extent comprises one ECCblock.
 74. An information recording apparatus according to claim 72,wherein the file management information comprises location informationindicating each real-time extent.
 75. An information recording apparatusaccording to claim 72, wherein the file management information comprisesidentification information for identifying the real-time file includingreal-time data.
 76. An information recording apparatus according toclaim 72, wherein the linking controller records a data type bit in anarea for recording physical additional information concerning eachsector within the linking loss extent, the data type bit being used foridentifying the linking loss extent; and wherein the data type bit forthe sector is set to 1 if a next sector is included within the linkingloss extent, unless the sector is a linking sector.
 77. An informationrecording apparatus according to claim 72, further comprising a runoutcontroller for recording the real-time data in a runout area within thelinking loss extent.
 78. A system controller for an informationrecording apparatus for recording a real-time file containing real-timedata on an information recording medium in such a manner that thereal-time data is continuously reproducible by a playback referencemodel, the real-time data comprising at least one of video data andaudio data, wherein the playback reference model includes: a pickup forreading the real-time data from the information recording medium; abuffer memory for temporarily storing the real-time data read by thepickup; and a decoder module for reading the real-time data from thebuffer memory for processing, wherein the information recording mediumcomprises a volume space for at least recording in sectors a filecomprising data and file management information for managing the file;wherein the system controller comprises a file system processing sectionfor: allocating at least two areas satisfying a real-time reproductioncondition from among a plurality of logically contiguous unused areaswithin the volume space, each of the at least two areas being designatedas a pre-allocated area; recording the real-time data and the filemanagement information; designating a set of logically contiguoussectors in which real-time data is recorded as a real-time extent; andgenerating the file management information for managing the real-timedata as the real-time file, wherein an (i+1)^(th) pre-allocated areaamong the at least two pre-allocated areas is positioned at a positionsatisfying a real-time reproduction condition defined as:T(i)≦(B(i−1)+D(i))/Vout,  wherein: T(i) represents a time required forthe pickup to access from an end of an i^(th) pre-allocated area amongthe at least two pre-allocated areas to a beginning of an (i+1)^(th)pre-allocated area among the at least two pre-allocated areas; B(i)represents an amount of data having been stored in the buffer memorywhen the pickup accesses from the end of the i^(th) pre-allocated areato the beginning of the (i+1)^(th) pre-allocated area, such thatB(i)=B(i−1)+D(i)/Vout×T(i), assuming that B(0)=0, D(i) represents anincrease in the amount of data having been stored in the buffer memoryresponsive to the pickup reading the data from the i^(th) pre-allocatedarea, such that D(i)=(Vin−Vout)×S(i)/Vin, wherein D(i) is corrected atleast to a value equal to or smaller than M−B(i−1) when D(i)>M−B(i−1),where M represents a size of the buffer memory; Vout represents a datatransfer rate when the data is transferred from the buffer memory to thedecoder module; Vin represents a data transfer rate when the data isread from the at pre-allocated are by the pickup and transferred to thebuffer memory; and S(i) represents a data size of the i^(th)pre-allocated area.
 79. A system controller for an information recordingapparatus for appending a real-time file containing real-time data on aninformation recording medium in such a manner that the real-time data iscontinuously reproducible by a playback reference model, the real-timedata comprising at least one of video data and audio data, wherein theplayback reference model includes: a pickup for reading the real-timedata from the information recording medium; a buffer memory fortemporarily storing the real-time data read by the pickup; and a decodermodule for reading the real-time data from the buffer memory forprocessing, wherein the information recording medium comprises a volumespace for at least recording in sectors a file comprising data and filemanagement information for managing the file, the real-time data isrecorded in at least one real-time extent each of which is allocated inlogically contiguous sectors within the volume space, wherein the systemcontroller comprises: a data amount calculation section for calculatingwhether or not each of the at least one real-time extent will cause anoverflow in an amount of data stored in the buffer memory if thereal-time extent is reproduced by the playback reference model;correcting the amount of data stored in the buffer memory to equal to orsmaller than the size of the buffer memory when it is calculated thatthe real-time extent will cause an overflow; calculating whether or notan underflow will occur in the amount of data stored in the buffermemory if the playback reference model accesses from the real-timeextent to a newly-allocated pre-allocated area; and searching for areal-time extent which will not cause an underflow, on accessing fromthe real-time extent to the pre-allocated area when it is calculatedthat an underflow will occur; a data recording section for recording inthe newly allocated pre-allocated area the real-time data alreadyrecorded in the real-time extent which will cause an underflow, andrecording real-time data to be appended in the newly-allocatedpre-allocated area; and a file structure processing section fordesignating a set of logically contiguous sectors in which real-timedata is recorded as a real-time extent and for generating and recordingthe file management information.
 80. A method for reproducing areal-time file containing real-time data on an information recordingmedium in such a manner that the real-time data is continuouslyreproducible by a playback reference model, the real-time datacomprising at least one of video data and audio data, wherein theplayback reference model includes: a pickup for reading the real-timedata from the information recording medium; a buffer memory fortemporarily storing the real-time data read by the pickup; and a decodermodule for reading the real-time data from the buffer memory forprocessing, wherein the information recording medium comprises a volumespace for at least recording in sectors a file comprising data and filemanagement information for managing the file, wherein the real-time datais recorded in at least two real-time extents each of which is allocatedin logically contiguous sectors within the volume space; and an(i+1)^(th) real-time extent among the at least two real-time extents ispositioned at a position satisfying a real-time reproduction conditiondefined as: T(i)≦(B(i1l)+D(i))/Vout,  wherein: T(i) represents a timerequired for the pickup to access from an end of an i^(th) real-timeextent among the at least two real-time extents to a beginning of the(i+1)^(th) real-time extent; B(i) represents an amount of data havingbeen stored in the buffer memory when the pickup accesses from the endof the i^(th) real-time extent to the beginning of the (i+1)^(th)real-time extent, such that B(i)=B(i−1)+D(i)−Vout×T(i), assuming thatB(0)=0, D(i) represents an increase in the amount of data having beenstored in the buffer memory responsive to the pickup reading the datafrom the i^(th) real-time extent, such that D(i)=(Vin−Vout)×S(i)/Vin,wherein D(i) is corrected at least to a value equal to or smaller thanM−B(i−1) when D(i)>M−B(i−1), where M represents a size of the buffermemory; Vout represents a data transfer rate when the data istransferred from the buffer memory to the decoder module; Vin representsa data transfer rate when the data is read from each of the at least tworeal-time extents by the pickup and transferred to the buffer memory;and S(i) represents a data size of the i^(th) real-time extent, whereinthe method comprises the steps of: reproducing the real-time file fromthe information recording medium by means of a disk drive; acquiringlocation information of each of the at least two real-time extents andidentification information indicating that the at least two real-timeextents are positioned in accordance with the real-time reproductioncondition; reading data from the at least two real-time extents at adata transfer rate which is equal to or greater than Vin of the playbackreference model; temporarily storing the real-time data which has beenread in the buffer memory; reading the data stored in the buffer memoryand decoding the data in a decoder; and accessing a next real-timeextent within the time T(i) of the playback reference model.
 81. Amethod according to claim 80, wherein the file management informationcomprises, as an extended attribute, information representing acondition under which the at least two real-time extents werepositioned, the method further comprising a step of: reading theextended attribute from the file management information, and informing areproduction mode to the disk drive based on the extended attributeprior to reproduction.
 82. A method for reproducing real-time data froman information recording medium comprising a volume space for at leastrecording in sectors a file comprising data and file managementinformation for managing the file, wherein: the data comprises real-timedata, the real-time data comprising at least one of video data and audiodata; the real-time data is recorded in at least one real-time extenteach of which is allocated in logically contiguous sectors within thevolume space; the file comprises at least one real-time extent; alinking loss extent is positioned before each of the at least onereal-time extent; and a linking gap is formed in the at least onereal-time extent, wherein the method comprises the steps of: determiningwhether or not the file is a real-time file containing real-time data;and performing a reproduction operation for data recorded in a real-timeextent, the reproduction operation being continuously performed withoutperforming a recovery process even if a reproduction error due toinvalid data recorded in the linking gap occurs.
 83. An informationreproduction apparatus for reproducing a real-time file containingreal-time data on an information recording medium in such a manner thatthe real-time data is continuously reproducible by a playback referencemodel, the real-time data comprising at least one of video data andaudio data, wherein the playback reference model includes: a pickup forreading the real-time data from the information recording medium; abuffer memory for temporarily storing the real-time data read by thepickup; and a decoder module for reading the real-time data from thebuffer memory for processing, wherein the information recording mediumcomprises a volume space for at least recording in sectors a filecomprising data and file management information for managing the file,wherein the real-time data is recorded in at least two real-time extentseach of which is allocated in logically contiguous sectors within thevolume space; and an (i+1)^(th) real-time extent among the at least tworeal-time extents is positioned at a position satisfying a real-timereproduction condition defined as: T(i)≦(B(i−1)+D(i))/Vout,  wherein:T(i) represents a time required for the pickup to access from an end ofan i^(th) real-time extent among the at least two real-time extents to abeginning of the (i+1)^(th) real-time extent; B(i) represents an amountof data having been stored in the buffer memory when the pickup accessesfrom the end of the i^(th) real-time extent to the beginning of the(i+1)^(th) real-time extent, such that B(i)=B(i−1)+D(i)−Vout×T(i),assuming that B(0)=0, D(i) represents an increase in the amount of datahaving been stored in the buffer memory responsive to the pickup readingthe data from the i^(th) real-time extent, such thatD(i)=(Vin−Vout)×S(i)/Vin, wherein D(i) is corrected at least to a valueequal to or smaller than M−B(i−1) when D(i)>M−B(i−1), where M representsa size of the buffer memory; Vout represents a data transfer rate whenthe data is transferred from the buffer memory to the decoder module;Vin represents a data transfer rate when the data is read from each ofthe at least two real-time extents by the pickup and transferred to thebuffer memory; and S(i) represents a data size of the i^(th) real-timeextent, wherein the information reproduction apparatus comprises: a diskdrive for reproducing the real-time file from the information recordingmedium; a file structure processing section for acquiring locationinformation of each of the at least two real-time extents andidentification information indicating that the at least two real-timeextents are positioned in accordance with the real-time reproductioncondition; a data reproducer for reading data from the at least tworeal-time extents at a data transfer rate which is equal to or greaterthan Vin of the playback reference model; a buffer memory fortemporarily storing the real-time data which has been read; and adecoder for reading the data stored in the buffer memory and decodingthe data, wherein a data reproduction performance which is determined asa function of an access performance and data transfer rate of the datareproducer and a size of the buffer memory satisfies a predetermineddata reproduction performance of the playback reference model.
 84. Aninformation reproduction apparatus according to claim 83, wherein thefile management information comprises, as an extended attribute,information representing a condition under which the at least tworeal-time extents were positioned, the information reproductionapparatus further comprising: a reproduction mode informing section forreading the extended attribute from the file management information, andinforming a reproduction mode to the disk drive based on the extendedattribute prior to reproduction.
 85. An information reproductionapparatus for reproducing a real-time file containing real-time data onan information recording medium comprising a volume space for at leastrecording in sectors a file comprising data and file managementinformation for managing the file, wherein: the data comprises real-timedata, the real-time data comprising at least one of video data and audiodata; the real-time data is recorded in at least one real-time extenteach of which is allocated in logically contiguous sectors within thevolume space; the file comprises at least one real-time extent; alinking loss extent is positioned before each of the at least onereal-time extent; and a linking gap is formed in the at least onereal-time extent, wherein the information reproduction apparatuscomprises: a file structure processing section for determining whetheror not the file is a real-time file containing real-time data; and adata reproducer for performing a reproduction operation for datarecorded in a real-time extent, the reproduction operation beingcontinuously performed without performing a recovery process even if areproduction error due to invalid data recorded in the linking gapoccurs.